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1

Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation  

SciTech Connect

According to the measurements made in this study, the only situation in which chromium (+6) could exist in a plutonium process solution is one in which a feed containing chromium is dissolved in a glass pot dissolver in high nitric acid concentration and at high temperature. But when the resulting feed is prepared for ion exchange, the chemical treatment reduces chromium to the +3 state. Any solution being processed through the evaporator will only contain chromium in the +3 state and any chromium salts remaining in the evaporator bottoms will be chromium +3 salts.

Smith, W.H.; Purdy, G.

1994-08-01

2

Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation  

SciTech Connect

This study was undertaken to determine if chromium(+6) could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium(+3) to chromium(+6) by nitric acid; and the reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium(+3) to chromium(+6) was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the (+6) oxidation state and would not exist in the (+6) state in the final process waste solutions.

Smith, W.H.; Purdy, G.M. [Los Alamos National Lab., NM (United States). Nuclear Materials Technology Div.] [Los Alamos National Lab., NM (United States). Nuclear Materials Technology Div.

1995-12-31

3

Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation  

SciTech Connect

This study was undertaken to determine if chromium +6 could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium +3 to chromium +6 by nitric. acid; and the reduction of chromium +6 back to chromium +3 by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium +3 to chromium +6 was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium +6 back to chromium +3 by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the +6 oxidation state and would not exist in the +6 state in the final process waste solutions.

Smith, W.H.; Purdy, G. [Los Alamos National Lab., NM (United States)

1995-12-01

4

STUDY OF URANIUM(IV) NITRATE AS REDUCTANT FOR PLUTONIUM. I. THE PREPARATION OF URANIUM(IV) NITRATE SOLUTIONS. Technical Report No. 118  

Microsoft Academic Search

Electrolytic reduction of uranyl nitrate solutions has been successfully used to prepare pure aqueous and TBP\\/SST uranium (IV) nitrate solutions for analytical purposes. It has also been used to produce hydrazine-nitrate-stabilized aqueous uranium (IV) nitrate solutions for use as plutonium reductant in a 'Purex' type aqueous reprocessing plant. Unstabilized aqueous and TBP\\/SST solutions containing more than 99.9% uranium (IV) have

E. Lopez-Menchero; L. Gehem; H. Eschrich; P. Hansen; J. Centeno; R. Aerts

1966-01-01

5

Gas pressure in sealed sample cans concentrated plutonium nitrate  

Microsoft Academic Search

The objective of this work was to establish as fact that the predominant gas evolved from concentrated plutonium nitrate solutions is oxygen. Four sample cans containing plutonium nitrate at various concentrations were sealed using plug valves equipped with pressure gages. The results obtained showed that the gas evolved from concentrated plutonium nitrate solutions is predominately oxygen. It is believed that

1953-01-01

6

ARRAYS OF BOTTLES OF PLUTONIUM NITRATE SOLUTION  

SciTech Connect

In October and November of 1981 thirteen approaches-to-critical were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight fitting Plexiglas® reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottles to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO3)4 solution with a Pu content of 105 g Pu/L and a free acid molarity H+ of 5.1. The plutonium was of low 240Pu (2.9 wt.%) content. These experiments were sponsored by Rockwell Hanford Operations because of the lack of experimental data on the criticality of arrays of bottles of Pu solution such as might be found in storage and handling at the Purex Facility at Hanford. The results of these experiments were used “to provide benchmark data to validate calculational codes used in criticality safety assessments of [the] plant configurations” (Ref. 1). Data for this evaluation were collected from the published report (Ref. 1), the approach to critical logbook, the experimenter’s logbook, and communication with the primary experimenter, B. Michael Durst. Of the 13 experiments preformed 10 were evaluated. One of the experiments was not evaluated because it had been thrown out by the experimenter, one was not evaluated because it was a repeat of another experiment and the third was not evaluated because it reported the critical number of bottles as being greater than 25. Seven of the thirteen evaluated experiments were determined to be acceptable benchmark experiments. A similar experiment using uranyl nitrate was benchmarked as U233-SOL-THERM-014.

Margaret A. Marshall

2012-09-01

7

Benchmark Evaluation of Plutonium Nitrate Solution Arrays  

SciTech Connect

In October and November of 1981 thirteen approach-to-critical experiments were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington, using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight fitting Plexiglas{reg_sign} reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottles to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO3)4 solution with a Pu content of 105 g Pu/L and a free acid molarity H+ of 5.1. The plutonium was of low 240Pu (2.9 wt.%) content. These experiments were performed to fill a gap in experimental data regarding criticality limits for storing and handling arrays of Pu solution in reprocessing facilities. Of the thirteen approach-to-critical experiments eleven resulted in extrapolations to critical configurations. Four of the approaches were extrapolated to the critical number of bottles; these were not evaluated further due to the large uncertainty associated with the modeling of a fraction of a bottle. The remaining seven approaches were extrapolated to critical array spacing of 3-4 and 4-4 arrays; these seven critical configurations were evaluation for inclusion as acceptable benchmark experiments in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook. Detailed and simple models of these configurations were created and the associated bias of these simplifications was determined to range from 0.00116 and 0.00162 {+-} 0.00006 ?keff. Monte Carlo analysis of all models was completed using MCNP5 with ENDF/BVII.0 neutron cross section libraries. A thorough uncertainty analysis of all critical, geometric, and material parameters was performed using parameter perturbation methods. It was found that uncertainty in the impurities in the polyethylene bottles, reflector position, bottle outer diameter, and critical array spacing had the largest effect. The total uncertainty ranged from 0.00651 to 0.00920 ?keff. Evaluation methods and results will be presented and discussed in greater detail in the full paper.

M. A. Marshall; J. D. Bess

2011-09-01

8

Exclusion of Nitrate from Frozen Aqueous Solutions  

NASA Astrophysics Data System (ADS)

Reactions occurring at the surface of ice, sea ice, and snow in Earth's cryosphere have an impact on the composition of the overlying atmosphere. In order to elucidate reaction mechanisms and model their contributions to atmospheric processes, the morphology of frozen aqueous surfaces and amounts of reactants contained therein must be determined. To this end, the exclusion of nitrate ions to the surface of frozen aqueous solutions has been studied by attenuated total reflection infrared spectroscopy (ATR-IR). In this technique the near-surface region of the frozen films are interrogated to a depth of a few hundred nanometers from the film-crystal interface. Aqueous solutions (0.001 to 0.01 M) of sodium nitrate (NaNO3), magnesium nitrate (Mg(NO3)2), and nitric acid (HNO3) were quickly frozen on the germanium ATR crystal and observed at a constant temperature of about -18°C. In addition to ice and the solutes, liquid water in varying amounts was observed in the spectra. The amount of nitrate in the surface liquid is three to four orders of magnitude higher than in the unfrozen solution. While all the nitrate salts exhibit exclusion to the unfrozen surface, the dynamics are different for different counter-ions. Results are compared to freezing point depression data and the predictions of equilibrium thermodynamics.

Marrocco, H. A.; Michelsen, R. R.

2013-12-01

9

Aqueous methods for recovery of plutonium from pyrochemical residues  

SciTech Connect

Salt residues generated during such pyrochemical processing of plutonium as direct oxide reduction (DOR), electrorefining (ER), and molten salt extraction sometimes contain more plutonium than the economic discard limit, and the plutonium must be recovered. Consequently, the authors have been studying aqueous methods for recovering the plutonium and producing discardable wastes. Most of the work has been the investigation of chloride anion exchange recovery with some interest in leaching and precipitation techniques.

Muscatello, A.C.; Killion, M.E.

1987-01-01

10

[Photodegradation of atenolol in aqueous nitrate solution].  

PubMed

The aqueous photolysis of beta-blocker atenolol (ATL) using Xe lamp as simulated solar irradiation source was investigated in the presence of nitrate ions. The effects of nitrate ion concentration, solution pH value, and concentration of bicarbonate and humic substance on the photodegradation of ATL were studied. The results showed that photodegradation of ATL in nitrate solution followed pseudo-first-order kinetics. The increasing concentration of nitrate ion promoted the photodegradation rate of ATL. The first-order rate constant increased from 0.002 26 min(-1) to 0.009 4 min(-1) with nitrate concentration increasing from 0 to 5 mmol x L(-1). Acidic or alkaline condition of the solution favored the photodegradation of ATL. Different concentration of bicarbonate showed insignificant effect of the degradation while the increasing concentration of fulvic acid showed inhibiting effect. Hydroxyl radical was determined to be formed during the photolysis process of ATL using isopropanol as molecular probe. The main photoproducts of ATL were identified by using SPE-LC-MS techniques and possible photoinduced degradation pathways in nitrate solution were proposed. PMID:22509585

Ji, Yue-Fei; Zeng, Chao; Meng, Cui; Yang, Xi; Gao, Shi-Xiang

2012-02-01

11

Influence of Acidity on Uranyl Nitrate Association in Aqueous Solutions: A Molecular Dynamics Simulation Study  

SciTech Connect

Uranyl ion complexation with water and nitrate is a key aspect of the uranium/plutonium extraction process. We have carried out a molecular dynamics simulation study to investigate this complexation process, including the molecular composition of the various complex species, the corresponding structure, and the equilibrium distribution of the complexes. The observed structures of the complexes suggest that in aqueous solution, uranyls are generally hydrated by 5 water molecules in the equatorial plane. When associating with nitrate ions, a water molecule is replaced by a nitrate ion, preserving the five-fold coordination and planar symmetry. Analysis of the pair correlation function between uranyl and nitrate suggests that nitrates bind to uranyl in aqueous solution mainly in a monodentate mode, although a small portion of bidentates occur. Dynamic association and dissociation between uranyls and nitrates take place in aqueous solution with a substantial amount of fluctuation in the number of various uranyl nitrate species. The average number of the uranyl mononitrate complexes shows a dependence on acid concentration consistent with equilibrium-constant analysis, namely, the concentration of [UO2NO3]+ increases with nitric acid concentration.

de Almeida, Valmor F [ORNL; Cui, Shengting [ORNL; Khomami, Bamin [ORNL; Ye, Xianggui [ORNL; Smith, Rodney Bryan [ORNL

2010-01-01

12

SULFATE AND NITRATE COATINGS ON MINERAL DUSTS: CRYSTALLINE OR AQUEOUS?  

E-print Network

02138, USA Keywords: Phase transition; Atmospheric Aerosols; Ammonium sulfate; Ammonium nitrate and are in aqueous form. For example, the deliquescence relative humidity of ammonium sulfate is 80% at 298 K while relative humidity; D = diameter (nm) of mineral core particle; AS = ammonium sulfate; AN = ammonium nitrate

13

EXTRACTION OF PLUTONIUM BY HEXONE FROM AQUEOUS SOLUTIONS CONTAINING NITRIC ACID  

Microsoft Academic Search

A general study has been made of the chemistry of plutonium-hexone systems containing nitric acid. The greater part of the work consisted of investigating the extent to which hexone extracted plutonium from aqueous solutions. A study of aqueous Pu(III) solutions in contact with hexone showed that the small amount of plutonium appearing in the hexone phase was in the 4-valent

1951-01-01

14

Criticality experiments with mixed plutonium and uranium nitrate solution at a plutonium fraction of 0.4 in slab geometry  

SciTech Connect

R. C. Lloyd of PNL has completed and published a series of critical experiments with mixed plutonium- uranium nitrate solutions (Reference 1). This series of critical experiments was part of an extensive program jointly sponsored by the U. S. Department of Energy (DOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan and was carried out in the mid-1980`s. The experiments evaluated here (published as Report PNL-6327) were performed with mixed plutonium- uranium nitrate solution in a variable thickness slab tank with two 106.7 cm square sides and a width that could be varied from 7.6 to 22.8 cm. The objective of these experiments was to obtain experimental data to permit the validation of computer codes for criticality calculations and of cross-section data to minimize the uncertainties inherent therein, so that facility safety, efficiency, and reliability could be enhanced. The concentrations of the solution were about 105, 293, and 435 g(Pu+U)/liter with a ratio of plutonium to total heavy metal (plutonium plus uranium) of about 0. 40 for all eight experiments. Four measurements were made with a water reflector, and four with no reflector. Following the publication of the initial PNL reports, considerable effort was devoted to an extensive reevaluation of this series of experiments by a collaboration of researchers from ORNL, PNL, and PNC (Reference 2). Their work resulted in a more accurate description of the ``as built`` hardware configuration and the materials specifications. For the evaluations in this report, the data published in Reference 2 by Smolen et al. is selected to supersede the original PNL report. Eight experiments have been evaluated and seven (063, 064, 071, 072, 074, 075, and 076) provide benchmark criticality data. Experiment 073 could not achieve criticality within vessel height limitations.

Pohl, B.A.; Keeton, S.C.

1997-09-01

15

Extraction of uranyl nitrate from concentrated aqueous salt solutions in diisoamyl methylphosponate  

SciTech Connect

The isotherm of extraction of uranyl nitrate from concentrated aqueous salt solutions of 100% diisoamyl methylphosphonate has been described. Allowance was made for formation of uranyl nitrate di- and trisolvates in the organic phase.

Pyartman, A.K.; Kopyrin, A.A.; Puzikov, E.A. [St. Petersburg Technological Institute (Russian Federation)

1995-09-10

16

Basis document for PFP plutonium nitrate ion exchange process in Room 228A  

SciTech Connect

The PFP facility currently has approximately 4300 liters of plutonium nitrate solution in storage. This material will be calcined by the Vertical Denigration Calciner (VDC) located in room 230C. However, part of the material needs to be purified to remove constituents that will interfere with the calcination process. An Ion Exchange process using Reillex{trademark} HPQ anion exchange resin was tested by the Plutonium Process Support Laboratories (PPSL) (I). The Ion exchange process is to be installed in glovebox HC-7 in room 228A/234-5Z. The plutonium separated from the interfering constituents will be in a concentrated condition ready to be calcined by the VDC in room 230C. The oxide product of the VDC will be placed into the 2736-Z vaults for long term storage.

Risenmay, H.R.

1997-04-23

17

Plutonium silicate alteration phases produced by aqueous corrosion of borosilicate glass.  

SciTech Connect

Borosilicate glasses loaded with {approx}10 wt % plutonium were found to produce plutonium-silicate alteration phases upon aqueous corrosion under a range of conditions. The phases observed were generally rich in lanthanide (Ln) elements and were related to the lanthanide orthosilicate phases of the monoclinic Ln{sub 2}SiO{sub 5} type. The composition of the phases was variable regarding [Ln]/[Pu] ratio, depending upon type of corrosion test and on the location within the alteration layer. The formation of these phases likely has implications for the incorporation of plutonium into silicate alteration phases during corrosion of titanate ceramics, high-level waste glasses, and spent nuclear fuel.

Fortner, J. A.; Mertz, C. J.; Bakel, A. J.; Finch, R. J.; Chamerlain, D. B.

1999-11-22

18

Effect of nitrate ions on the oxidation of iodide ions during the dissolution of ?-irradiated NaCl in aqueous binary mixture of iodide and nitrate  

Microsoft Academic Search

It is now well established that the oxidation of iodide ions and the reduction of nitrate ions take place when -irradiated sodium chloride is dissolved in aqueous iodide and nitrate solutions, respectively. The yield of iodine decreases and that of nitrite increases with increasing concentration of nitrate in a binary mixture of iodide and nitrate when the irradiated salt is

C. D. Kalkar; S. V. Doshi

1988-01-01

19

Extraction of uranyl nitrate from concentrated aqueous salt solutions by tributyl phosphate  

SciTech Connect

Equations have been proposed for describing isotherms of extraction of uranyl nitrate from concentrated aqueous salt solutions by neat tri-n-butyl phosphate, with account taken of variations of activity coefficients of the components in organic phase over a wide range of its compositions. The constants of extraction equilibria, calculated for a standard hypothetical 1 M aqueous solution of uranyl nitrate and the state of pure components in organic phase with a mole fraction of 1, have been determined assuming formation of uranyl nitrate disolvate and trisolvate in the organic phase. The excessive thermodynamic functions of mixing tri-n-butyl phosphate with uranyl nitrate disolvate are presented.

Pyartman, A.K.; Kopyrin, A.A.; Puzikov, E.A.

1995-01-01

20

Effects of inhaled plutonium nitrate on bone and liver in dogs  

SciTech Connect

The life-span biological effects of inhaled soluble, alpha-emitting radionuclides deposited in the skeleton and liver were studied in 5 groups of 20 beagles exposed to initial lung depositions ranging from 0.48 to 518 Bq/g of lung. Average plutonium amounts in the lungs decreased to approximately 1% of the final body deposition in dogs surviving 5 years or more; more than 90% of the final depositions accumulated in the liver and skeleton. The liver-to-skeletal ratio of deposited plutonium was 0.83. The incidence of bone tumors, primarily osteogenic sarcomas causing early mortality, at final group average skeletal depositions of 15.8, 2.1, and 0.5 Bq/g was, respectively, 85%, 50%, and 5%; there were no bone tumors in exposure groups with mean average depositions lower than 0.5 Bq/g. Elevated serum liver enzyme levels were observed in exposure groups down to 1.3 Bq/g. The incidence of liver tumors at final group average liver depositions of 6.9, 1.3, 0.2, and 0.1 Bq/g, was, respectively, 25%, 15%, 15%, and 15%; one hepatoma occurred among 40 control dogs. The risk of the liver cancer produced by inhaled plutonium nitrate was difficult to assess due to the competing risks of life shortening from lung and bone tumors.

Dagle, G.E.; Weller, R.E.; Watson, C.R.; Buschbom, R.L. [Pacific Northwest Lab., Richland, WA (United States). Biology and Chemistry Dept.

1994-04-01

21

Formulas to Correct Excess Pressure and Pressure Shift to be Used in Volume Measurement for Plutonium Nitrate Solution  

Microsoft Academic Search

Excess pressure caused by the bubble and the pressure shift resulting from the air column in a dip-tube pressure measurement are the error sources to be considered for highly accurate density, level, and volume determination of plutonium nitrate solution in a tank. A new approach to estimate the maximum, the minimum, and the average of oscillating excess pressure as a

Takashi Hosoma; Masanori Aritomi; Tsunemichi Kawa

2000-01-01

22

Chemical reduction kinetics of nitrate in aqueous solution by Mg\\/Cu bimetallic particles  

Microsoft Academic Search

Synthesized magnesium\\/copper (Mg\\/Cu) bimetallic particles have shown good potential for use in the reduction of nitrate from aqueous solutions. This study was conducted to investigate the main factors affecting the kinetics of nitrate reduction by Mg\\/Cu particles (<100 µm) in uncontrolled reaction conditions. The Mg\\/Cu bimetallic particles removed the majority of the various nitrate concentrations tested (50, 100, 150, 200

S. B. Mortazavi; B. Ramavandi; G. Moussavi

2011-01-01

23

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions  

E-print Network

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

American Society for Testing and Materials. Philadelphia

2010-01-01

24

Method of separating thorium from plutonium  

DOEpatents

A method is described for chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

Clifton, D.G.; Blum, T.W.

1984-07-10

25

Method of separating thorium from plutonium  

DOEpatents

A method of chemically separating plutonium from thorium. Plutonium and thorium to be separated are dissolved in an aqueous feed solution, preferably as the nitrate salts. The feed solution is acidified and sodium nitrite is added to the solution to adjust the valence of the plutonium to the +4 state. A chloride salt, preferably sodium chloride, is then added to the solution to induce formation of an anionic plutonium chloride complex. The anionic plutonium chloride complex and the thorium in solution are then separated by ion exchange on a strong base anion exchange column.

Clifton, David G. (Los Alamos, NM); Blum, Thomas W. (Los Alamos, NM)

1984-01-01

26

Nitrate removal from aqueous solution by adsorption onto various materials.  

PubMed

In this study sepiolite, sepiolite activated by HCl, slag and powdered activated carbon were used as adsorbent with a particle size was between 71 and 80 microm (200-170 mesh). NaNO3 solution (100 mg/l) was used in batch adsorption experiments for nitrate removal. First kinetic studies were carried out and it was determined that slag was not effective for nitrate removal, then contact time, pH and adsorbent dosage effects on nitrate removal by adsorption were investigated using other adsorbents except slag. The equilibrium time was found to be 30, 45, 5 min for sepiolite, powdered activated carbon and activated sepiolite, respectively. The most effective pH value for nitrate removal was 2 for powdered activated carbon. pH value did not affect nitrate removal significantly for other adsorbents. Adsorbent dosages were varied from 5 to 20 g/l solutions. An increase in adsorbent dosage increased the percent removal of nitrate. A series of isotherm studies were undertaken and the data evaluated for compliance with the Langmuir and Freundlich isotherm models. To investigate the adsorption mechanisms, three simplified kinetic models, i.e., first-, second-order and intraparticle diffusion were tested. Adsorption followed second-order rate kinetics. The correlation coefficients for second order kinetic model are greater than 0.996. Experimental data show that sepiolite activated by HCl was effective for nitrate removal. PMID:15225942

Oztürk, Ne?e; Bekta?, T Ennil

2004-08-01

27

Nitrate removal from aqueous solution by adsorption onto various materials  

Microsoft Academic Search

In this study sepiolite, sepiolite activated by HCl, slag and powdered activated carbon were used as adsorbent with a particle size was between 71 and 80?m (200–170mesh). NaNO3 solution (100mg\\/l) was used in batch adsorption experiments for nitrate removal. First kinetic studies were carried out and it was determined that slag was not effective for nitrate removal, then contact time,

Ne?e Öztürk

2004-01-01

28

Synthesis and Structures of Plutonyl Nitrate Complexes: Is Plutonium Heptavalent in PuO3(NO3)2(-) ?  

PubMed

Gas-phase plutonium nitrate anion complexes were produced by electrospray ionization (ESI) of a plutonium nitrate solution. The ESI mass spectrum included species with all four of the common oxidation states of plutonium: Pu(III), Pu(IV), Pu(V), and Pu(VI). Plutonium nitrate complexes were isolated in a quadrupole ion trap and subjected to collision-induced dissociation (CID). CID of complexes of the general formula PuOx(NO3)y(-) resulted in the elimination of NO2 to produce PuOx+1(NO3)y-1(-), which in most cases corresponds to an increase in the oxidation state of plutonium. Plutonyl species, Pu(V)O2(NO3)2(-) and Pu(VI)O2(NO3)3(-), were produced from Pu(III)(NO3)4(-) and Pu(IV)(NO3)5(-), respectively, by the elimination of two NO2 molecules. CID of Pu(VI)O2(NO3)3(-) resulted in NO2 elimination to yield PuO3(NO3)2(-), in which the oxidation state of plutonium could be VII, a known oxidation state in condensed phase but not yet in the gas phase. Density functional theory confirmed the nature of Pu(V)O2(NO3)2(-) and Pu(VI)O2(NO3)3(-) as plutonyl(V/VI) cores coordinated by bidentate equatorial nitrate ligands. The computed structure of PuO3(NO3)2(-) is essentially a plutonyl(VI) core, Pu(VI)O2(2+), coordinated in the equatorial plane by two nitrate ligands and one radical oxygen atom. The computations indicate that in the ground spin-orbit free state of PuO3(NO3)2(-), the unpaired electron of the oxygen atom is antiferromagnetically coupled to the spin-triplet state of the plutonyl core. The results indicate that Pu(VII) is not a readily accessible oxidation state in the gas phase, despite that it is stable in solution and solids, but rather that a Pu(VI)-O· bonding configuration is favored, in which an oxygen radical is involved. PMID:25695878

Maurice, Rémi; Renault, Eric; Gong, Yu; Rutkowski, Philip X; Gibson, John K

2015-03-01

29

Nitrate Anion Exchange in Pu-238 Aqueous Scrap Recovery Operations  

SciTech Connect

Strong base, nitrate anion exchange (IX) is crucial to the purification of {sup 238}Pu solution feedstocks with gross levels of impurities. This paper discusses the work involved in bench scale experiments to optimize the nitrate anion exchange process. In particular, results are presented of experiments conducted to (a) demonstrate that high levels of impurities can be separated from {sup 238}Pu solutions via nitrate anion exchange and, (b) work out chemical pretreatment methodology to adjust and maintain {sup 238}Pu in the IV oxidation state to optimize the Pu(IV)-hexanitrato anionic complex sorption to Reillex-HPQ resin. Additional experiments performed to determine the best chemical treatment methodology to enhance recovery of sorbed Pu from the resin, and VIS-NIR absorption studies to determine the steady state equilibrium of Pu(IV), Pu(III), and Pu(VI) in nitric acid are discussed.

Pansoy-Hjelvik, M.E.; Silver, G.L.; Reimus, M.A.H.; Ramsey, K.B.

1999-01-31

30

Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO  

SciTech Connect

DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

Spencer, B.B.

1995-08-01

31

Plutonium  

NASA Astrophysics Data System (ADS)

The element plutonium occupies a unique place in the history of chemistry, physics, technology, and international relations. After the initial discovery based on submicrogram amounts, it is now generated by transmutation of uranium in nuclear reactors on a large scale, and has been separated in ton quantities in large industrial facilities. The intense interest in plutonium resulted fromthe dual-use scenario of domestic power production and nuclear weapons - drawing energy from an atomic nucleus that can produce a factor of millions in energy output relative to chemical energy sources. Indeed, within 5 years of its original synthesis, the primary use of plutonium was for the release of nuclear energy in weapons of unprecedented power, and it seemed that the new element might lead the human race to the brink of self-annihilation. Instead, it has forced the human race to govern itself without resorting to nuclear war over the past 60 years. Plutonium evokes the entire gamut of human emotions, from good to evil, from hope to despair, from the salvation of humanity to its utter destruction. There is no other element in the periodic table that has had such a profound impact on the consciousness of mankind.

Clark, David L.; Hecker, Siegfried S.; Jarvinen, Gordon D.; Neu, Mary P.

32

Spatial distribution of nitrate and nitrite anions at the liquid/vapor interface of aqueous solutions.  

PubMed

Depth-resolved ion spatial distributions of nitrate and nitrite anions in aqueous solution have been quantitatively measured using X-ray photoemission spectroscopy on a 15 microm aqueous liquid jet containing 3 M NaNO(3), 3 M NaNO(2), or an equimolar mixture of the two. The surface region, which extends to photoelectron kinetic energies of 400-500 eV, is partially depleted in anions relative to the bulk 3 M concentration. The nitrate and nitrite solutions exhibit similar depth-dependent anion profiles. The results presented here are compared with recent molecular dynamics simulations of a NaNO(3) solution and are found to agree at high photoelectron kinetic energies. At shallower probe depths, the experiment measured a surface anion concentration less than that predicted by theory. Possible origins of the discrepancy are discussed in terms of the confined size of the simulation box and uncertainties that remain in regard to the inelastic mean free path of photoelectrons in aqueous media. The importance of our findings is discussed in relation to the observed increase in photochemical activity of nitrate-containing aerosols in the atmosphere. PMID:19530722

Brown, Matthew A; Winter, Bernd; Faubel, Manfred; Hemminger, John C

2009-06-24

33

Radiolysis of hexavalent plutonium in solutions of uranyl nitrate containing fission product simulants  

NASA Astrophysics Data System (ADS)

The effect of the inherent radioactivity on the chemical state of plutonium ions in solution was recognized very shortly after the first macroscopic amounts of plutonium became available and early studies were conducted as part of the Manhattan Project. However, the behavior of plutonium ions, in nitric acid especially, has been found to be somewhat complex, so much so that a relatively modern summary paper included the comment that, "The vast amount of work carried out in nitric acid solutions can not be adequately summarized. Suffice it to say results in these solutions are plagued with irreproducibility and induction periods…" Needless to say, the presence of other ions in solution, as occurs when irradiated nuclear fuel is dissolved, further complicates matters. The purpose of the work described below was to add to the rather small amount of qualitative data available relating to the radiolytic behavior of plutonium in solutions of irradiated nuclear fuel.

Rance, Peter J. W.; Zilberman, B. Ya.; Akopov, G. A.

2000-07-01

34

Room temperature electrodeposition and characterization of bismuth ferric oxide (BFO) thin films from aqueous nitrate bath  

NASA Astrophysics Data System (ADS)

Bismuth ferric oxide (BFO) thin films were prepared on fluorine doped tin oxide (FTO) coated glass substrates using electrodeposition method from aqueous nitrate bath at room temperature. The various preparative parameters, such as bath composition, current density, deposition time, etc were optimized to get good quality BFO thin films. The structural, surface morphological, optical and dielectrical properties of the films were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption and dielectric measurement techniques. The results show that electrodeposition method allows to synthesis BFO films. The films are free from pinholes and cracks. The magnitudes of dielectric constant and loss tangent showed inverse frequency dependence.

Gujar, T. P.; Shinde, V. R.; Kulkarni, S. S.; Pathan, H. M.; Lokhande, C. D.

2006-03-01

35

Aqueous nitrate waste treatment: Technology comparison, cost/benefit, and market analysis  

SciTech Connect

The purpose of this analysis is to provide information necessary for the Department of Energy (DOE) to evaluate the practical utility of the Nitrate to Ammonia and Ceramic or Glass (NAC/NAG/NAX) process, which is under development in the Oak Ridge National Laboratory. The NAC/NACx/NAX process can convert aqueous radioactive nitrate-laden waste to a glass, ceramic, or grout solid waste form. The tasks include, but are not limited to, the following: Identify current commercial technologies to meet hazardous and radiological waste disposal requirements. The technologies may be thermal or non-thermal but must be all inclusive (i.e., must convert a radionuclide-containing nitrate waste with a pH around 12 to a stable form that can be disposed at permitted facilities); evaluate and compare DOE-sponsored vitrification, grouting, and minimum additive waste stabilization projects for life-cycle costs; compare the technologies above with respect to material costs, capital equipment costs, operating costs, and operating efficiencies. For the NAC/NAG/NAX process, assume aluminum reactant is government furnished and ammonia gas may be marketed; compare the identified technologies with respect to frequency of use within DOE for environmental management applications with appropriate rationale for use; Assess the potential size of the DOE market for the NAC/NAG/NAX process; assess and off-gas issues; and compare with international technologies, including life-cycle estimates.

Not Available

1994-01-01

36

Water Structure at the Air-Aqueous Interface of Divalent Cation and Nitrate Solutions Man Xu, Rick Spinney, and Heather C. Allen*  

E-print Network

Water Structure at the Air-Aqueous Interface of Divalent Cation and Nitrate Solutions Man Xu, Rick, Columbus, Ohio 43210 ReceiVed: July 24, 2008; ReVised Manuscript ReceiVed: December 4, 2008 The water surface structure of aqueous magnesium, calcium, and strontium nitrate solutions with six to seven water

37

Crystals Formed at 293 K by Aqueous Sulfate-Nitrate-Ammonium-Proton Aerosol Julie C. Schlenker, Adam Malinowski, Scot T. Martin,* Hui-Ming Hung, and Yinon Rudich  

E-print Network

Crystals Formed at 293 K by Aqueous Sulfate-Nitrate-Ammonium-Proton Aerosol Particles Julie C particles are commonly internal mixtures of sulfate, nitrate, ammonium, other inorganic and organic ions, nondissociated organic molecules, and insoluble inclusions, such as soot or mineral dust.7 Sulfate, nitrate

38

Nitrate Anions and Ion Pairing at the Air-Aqueous Interface Man Xu, Cheng Y. Tang, Aaron M. Jubb, Xiangke Chen, and Heather C. Allen*  

E-print Network

radical levels in and above snowpacks originate from the photolysis of nitrate ions in snow and iceNitrate Anions and Ion Pairing at the Air-Aqueous Interface Man Xu, Cheng Y. Tang, Aaron M. Jubb, Columbus, Ohio 43210 ReceiVed: June 18, 2008; ReVised Manuscript ReceiVed: October 31, 2008 Nitrate ions

39

Criticality Experiments with Mixed Plutonium and Uranium Nitrate Solution at a Plutonium Fraction of 0.5 in Annular Cylindrical Geometry  

SciTech Connect

A series of critical experiments was completed with mixed plutonium-uranium solutions having Pu/(Pu + U) ratios of approximately 0.5. These experiments were a part of the Criticality Data Development Program between the United States Department of Energy (USDOE), and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of, and data from, the experiments are included in this report. The experiments were performed with mixed plutonium-uranium solutions in annular cylindrical geometry. The measurements were made with a water reflector. The central region included a concrete annular cylinder containing B{sub 4}C. Interior to the concrete insert was a stainless steel bottle containing plutonium-uranium solution. The concentration of the solution in the annular region was varied from 116 to 433 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was 52% for all experiments.

Lloyd, RC

1988-04-01

40

Release of nitrous acid and nitrogen dioxide from nitrate photolysis in acidic aqueous solutions.  

PubMed

Nitrate (NO3(-)) is an abundant component of aerosols, boundary layer surface films, and surface water. Photolysis of NO3(-) leads to NO2 and HONO, both of which play important roles in tropospheric ozone and OH production. Field and laboratory studies suggest that NO3¯ photochemistry is a more important source of HONO than once thought, although a mechanistic understanding of the variables controlling this process is lacking. We present results of cavity-enhanced absorption spectroscopy measurements of NO2 and HONO emitted during photodegradation of aqueous NO3(-) under acidic conditions. Nitrous acid is formed in higher quantities at pH 2-4 than expected based on consideration of primary photochemical channels alone. Both experimental and modeled results indicate that the additional HONO is not due to enhanced NO3(-) absorption cross sections or effective quantum yields, but rather to secondary reactions of NO2 in solution. We find that NO2 is more efficiently hydrolyzed in solution when it is generated in situ during NO3(-) photolysis than for the heterogeneous system where mass transfer of gaseous NO2 into bulk solution is prohibitively slow. The presence of nonchromophoric OH scavengers that are naturally present in the environment increases HONO production 4-fold, and therefore play an important role in enhancing daytime HONO formation from NO3(-) photochemistry. PMID:25271384

Scharko, Nicole K; Berke, Andrew E; Raff, Jonathan D

2014-10-21

41

Caffeine as non-toxic corrosion inhibitor for copper in aqueous solutions of potassium nitrate  

NASA Astrophysics Data System (ADS)

Different electrochemical methods were employed in order to confirm the ability of caffeine (1,3,7-trimethylxanthine) to inhibit the corrosion processes of copper in aqueous potassium nitrate solutions in the absence and in the presence of chloride. Some experiments were repeated in potassium perchlorate in order to compare the influence of the medium. The interaction between the organic compound and the electrode surface occurs independently of the electrode potential. However, maximum interaction was observed at 0.0 V (Ag/AgCl) in aerated solutions, and at -0.25 V (Ag/AgCl) in deaerated solutions. The presence of the organic compound adsorbed on the electrode surface was confirmed by comparing the voltammograms of copper electrode in the absence and presence of 1.5 mmol L -1 of dissolved caffeine. The same results were observed by comparing polarization curves in the absence and in the presence of caffeine. Anodic currents decrease noticeably in the presence of the organic compound. Chronoamperometric experiments were conclusive to prove the inhibitor capability of caffeine to decrease the corrosion dissolution processes of copper under anodic polarization.

Fallavena, Thuanny; Antonow, Muriel; Gonçalves, Reinaldo Simões

2006-11-01

42

Aqueous biphasic plutonium oxide extraction process with pH and particle control  

DOEpatents

A method is described for simultaneously partitioning a metal oxide and silica from a material containing silica and the metal oxide, using a biphasic aqueous medium having immiscible salt and polymer phases. 2 figs.

Chaiko, D.J.; Mensah-Biney, R.

1997-04-29

43

Plutonium Chemistry in the UREX+ Separation Processes  

SciTech Connect

The project "Plutonium Chemistry in the UREX+ Separation Processes” is led by Dr. Alena Paulenova of Oregon State University under collaboration with Dr. George Vandegrift of ANL and Dr. Ken Czerwinski of the University of Nevada at Las Vegas. The objective of the project is to examine the chemical speciation of plutonium in UREX+ (uranium/tributylphosphate) extraction processes for advanced fuel technology. Researchers will analyze the change in speciation using existing thermodynamics and kinetic computer codes to examine the speciation of plutonium in aqueous and organic phases. They will examine the different oxidation states of plutonium to find the relative distribution between the aqueous and organic phases under various conditions such as different concentrations of nitric acid, total nitrates, or actinide ions. They will also utilize techniques such as X-ray absorbance spectroscopy and small-angle neutron scattering for determining plutonium and uranium speciation in all separation stages. The project started in April 2005 and is scheduled for completion in March 2008.

ALena Paulenova; George F. Vandegrift, III; Kenneth R. Czerwinski

2009-10-01

44

Chemical species of plutonium in Hanford radioactive tank waste  

SciTech Connect

Large quantities of radioactive wastes have been generated at the Hanford Site over its operating life. The wastes with the highest activities are stored underground in 177 large (mostly one million gallon volume) concrete tanks with steel liners. The wastes contain processing chemicals, cladding chemicals, fission products, and actinides that were neutralized to a basic pH before addition to the tanks to prevent corrosion of the steel liners. Because the mission of the Hanford Site was to provide plutonium for defense purposes, the amount of plutonium lost to the wastes was relatively small. The best estimate of the amount of plutonium lost to all the waste tanks is about 500 kg. Given uncertainties in the measurements, some estimates are as high as 1,000 kg (Roetman et al. 1994). The wastes generally consist of (1) a sludge layer generated by precipitation of dissolved metals from aqueous wastes solutions during neutralization with sodium hydroxide, (2) a salt cake layer formed by crystallization of salts after evaporation of the supernate solution, and (3) an aqueous supernate solution that exists as a separate layer or as liquid contained in cavities between sludge or salt cake particles. The identity of chemical species of plutonium in these wastes will allow a better understanding of the behavior of the plutonium during storage in tanks, retrieval of the wastes, and processing of the wastes. Plutonium chemistry in the wastes is important to criticality and environmental concerns, and in processing the wastes for final disposal. Plutonium has been found to exist mainly in the sludge layers of the tanks along with other precipitated metal hydrous oxides. This is expected due to its low solubility in basic aqueous solutions. Tank supernate solutions do not contain high concentrations of plutonium even though some tanks contain high concentrations of complexing agents. The solutions also contain significant concentrations of hydroxide which competes with other potential complexants. The sodium nitrate and sodium phosphate salts that form most of the salt cake layers have little interaction with plutonium in the wastes and contain relatively small plutonium concentrations. For these reasons the authors consider plutonium species in the sludges and supernate solutions only. The low concentrations of plutonium in waste tank supernate solutions and in the solid sludges prevent identification of chemical species of plutonium by ordinary analytical techniques. Spectrophotometric measurements are not sensitive enough to identify plutons oxidation states or complexes in these waste solutions. Identification of solid phases containing plutonium in sludge solids by x-ray diffraction or by microscopic techniques would be extremely difficult. Because of these technical problems, plutonium speciation was extrapolated from known behavior observed in laboratory studies of synthetic waste or of more chemically simple systems.

Barney, G.S.

1997-10-22

45

An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions  

PubMed Central

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH4)2SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate. PMID:24145916

Campos, Inmaculada; Pascual, Lluis; Soto, Juan; Gil-Sánchez, Luis; Martínez-Máñez, Ramón

2013-01-01

46

Nitrate-induced photodegradation of atenolol in aqueous solution: kinetics, toxicity and degradation pathways.  

PubMed

The extensive utilization of ?-blockers worldwide led to frequent detection in natural water. In this study the photolysis behavior of atenolol (ATL) and toxicity of its photodegradation products were investigated in the presence of nitrate ions. The results showed that ATL photodegradation followed pseudo-first-order kinetics upon simulated solar irradiation. The photodegradation was found to be dependent on nitrate concentration and increasing the nitrate from 0.5 mML(-1) to 10 mML(-1) led to the enhancement of rate constant from 0.00101 min(-1) to 0.00716 min(-1). Hydroxyl radical was determined to play a key role in the photolysis process by using isopropanol as molecular probe. Increasing the solution pH from 4.8 to 10.4, the photodegradation rate slightly decreased from 0.00246 min(-1) to 0.00195 min(-1), probably due to pH-dependent effect of nitrate-induced .OH formation. Bicarbonate decreased the photodegradation of ATL in the presence of nitrate ions mainly through pH effect, while humic substance inhibited the photodegradation via both attenuating light and competing radicals. Upon irradiation for 240 min, only 10% reduction of total organic carbon (TOC) can be achieved in spite of 72% transformation rate of ATL, implying a majority of ATL transformed into intermediate products rather than complete mineralization. The main photoproducts of ATL were identified by using solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) techniques and possible nitrate-induced photodegradation pathways were proposed. The toxicity of the phototransformation products was evaluated using aquatic species Daphnia magna, and the results revealed that photodegradation was an effective mechanism for ATL toxicity reduction in natural waters. PMID:22497785

Ji, Yuefei; Zeng, Chao; Ferronato, Corinne; Chovelon, Jean-Marc; Yang, Xi

2012-07-01

47

Coordination and Hydrolysis of Plutonium Ions in Aqueous Solution using Car-Parrinello Molecular Dynamics Free Energy Simulations  

SciTech Connect

Car-Parrinello molecular dynamics (CPMD) simulations have been used to examine the hydration structures, coordination energetics and the first hydrolysis constants of Pu3+, Pu4+, PuO2+ and PuO22+ ions in aqueous solution at 300 K. The coordination numbers and structural properties of the first shell of these ions are in good agreement with available experimental estimates. The hexavalent PuO22+ species is coordinated to 5 aquo ligands while the pentavalent PuO2+ complex is coordinated to 4 aquo ligands. The Pu3+ and Pu4+ ions are both coordinated to 8 water molecules. The first hydrolysis constants obtained for Pu3+ and PuO22+ are 6.65 and 5.70 respectively, all within 0.3 pH units of the experimental values (6.90 and 5.50 respectively). The hydrolysis constant of Pu4+, 0.17, disagrees with the value of -0.60 in the most recent update of the Nuclear Energy Agency Thermochemical Database (NEA-TDB) but supports recent experimental findings. The hydrolysis constant of PuO2+, 9.51, supports the experimental results of Bennett et al. (Radiochim. Act. 1992, 56, 15). A correlation between the pKa of the first hydrolysis reaction and the effective charge of the plutonium center was found.

Odoh, Samuel O.; Bylaska, Eric J.; De Jong, Wibe A.

2013-11-27

48

Synthesis and characterization of some new mono- and diamide complexes of plutonium(IV) and dioxouranium(VI) nitrates  

Microsoft Academic Search

Plutonium tetranitrato complexes with N,N?-dialkyl monoamides A[A = dibutyl derivatives of hexanamide (DBHA), octanamide (DBOA)] and tetraalkyl diamides B [B = tetrabutyl, tetraisobutyl and tetrahexyl malonamide (TBMA, TIBMA, THMA)] have been isolated and characterized as Pu(NO3)4 · 3A and Pu(NO)3)4 · 2B, respectively. Complexes with diamides such as Pu(NO3)4 · 2TBMA and Pu(NO3)4 · 2TIBMA were isolated as solids while

P. B. Ruikar; M. S. Nagar

1995-01-01

49

Carcinogenesis and Inflammatory Effects of Plutonium-Nitrate Retention in an Exposed Nuclear Worker and Beagle Dogs.  

SciTech Connect

The genetic and inflammatory response pathways elicited following plutonium exposure in archival lung tissue of an occupationally exposed human and experimentally exposed beagle dogs were investigated. These pathways include: tissue injury, apoptosis and gene expression modifications related to carcinogenesis and inflammation. In order to determine which pathways are involved, multiple lung samples from a plutonium exposed worker (Case 0269), a human control (Case 0385), and plutonium exposed beagle dogs were examined using histological staining and immunohistochemistry. Examinations were performed to identify target tissues at risk of radiation-induced fibrosis, inflammation, and carcinogenesis. Case 0269 showed interstitial fibrosis in peripheral and subpleural regions of the lung, but no pulmonary tumors. In contrast, the dogs with similar and higher doses showed pulmonary tumors primarily in brochiolo-alveolar, peripheral and subpleural alveolar regions. The TUNEL assay showed slight elevation of apoptosis in tracheal mucosa, tumor cells, and nuclear debris was present in the inflammatory regions of alveoli and lymph nodes of both the human and the dogs. The expression of apoptosis and a number of chemokine/cytokine genes was slightly but not significantly elevated in protein or gene levels compared to that of the control samples. In the beagles, mucous production was increased in the airway epithelial goblet cells and glands of trachea, and a number of chemokine/cytokine genes showed positive immunoreactivity. This analysis of archival tissue from an accidentally exposed worker and in a large animal model provides valuable information on the effects of long-term retention of plutonium in the respiratory tract and the histological evaluation study may impact mechanistic studies of radiation carcinogenesis.

Nielsen, Christopher E.; Wang, Xihai; Robinson, Robert J.; Brooks, Antone L.; Lovaglio, Jamie A.; Patton, Kristin M.; McComish, Stacey; Tolmachev, Sergei Y.; Morgan, William F.

2014-01-01

50

Apparent molar and partial molar volumes of aqueous ceric ammonium nitrate solutions at 20, 25, 30, and 35°C  

NASA Astrophysics Data System (ADS)

Present paper reports the measured densities (?) and refractive indices ( n D) of aqueous solutions of ceric ammonium nitrate (CAN) at 20, 25, 30, and 35°C in different concentrations of solution. Apparent molar volumes (?v) have been calculated from the density data at different temperatures and fitted to Massons relation to get limiting partial molar volumes (?{v/0}) of CAN. Refractive index data were fitted to linear dependence over concentration of solutions and values of constant K and n {D/0} for different temperatures were evaluated. Specific refractions ( R D) of solutions were calculated from the refractive index and density data. Concentration and temperature effects on experimental and derived properties have been discussed in terms of structural interactions.

Deosarkar, S. D.; Wanale, S. G.; Shelke, M. P.

2014-07-01

51

Effects of iron surface pretreatment on kinetics of aqueous nitrate reduction.  

PubMed

Using hydrogen gas at 400 degrees C to activate iron surface was proposed to remove nitrate (40 mg NL(-1)) in a HEPES buffer solution at pH value between 6.5 and 7.5. Compared with the nonpretreated iron, the first-order reaction rate constant (kobs) was increased 4.7 times by pretreated iron, and the lag of the early period disappeared. Normalized to iron surface area concentration, the specific rate constant (kSA) was increased approximately by a factor of 6 using hydrogen reduction (0.0020 min(-1)m(-2)L for nonpretreated iron and 0.0128 min(-1)m(-2)L for pretreated iron). The reactivity of aged iron covered by a complex mixture of iron oxides (soaking in nitrate solution for 60 days) were restored by hydrogen gas at 400 degrees C. Scanning electron microscopy (SEM) and temperature-programmed reduction (TPR) exhibited visibly cleaner without pitting and cracking and less oxygen fraction on pretreated iron surface relative to nonpretreated iron. Activation energies (Ea) of nitrate reduction over the temperature range of 10-45 degrees C were 46.0 kJ mol(-1) for nonpretreated iron, and 32.0 kJ mol(-1) for pretreated iron, indicating chemical reaction control, rather than diffusion. The results indicated that this enhancement was attributed to the increase in active site concentration on iron surface by hydrogen reduction. PMID:16095813

Liou, Ya Hsuan; Lo, Shang-Lien; Lin, Chin-Jung; Kuan, Wen Hui; Weng, Shih Chi

2005-11-11

52

Preparation of activated carbons from Iris tectorum employing ferric nitrate as dopant for removal of tetracycline from aqueous solutions.  

PubMed

Ferric nitrate was employed to modify activated carbon prepared from Iris tectorum during H?PO? activation and ability of prepared activated carbon for removal of tetracycline (TC) was investigated. The properties of the activated carbon samples with or without ferric nitrate, ITAC-Fe and ITAC, were measured by scanning electron microscopy (SEM), N? adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR) and Boehm's titration. The results showed that mixing with iron increased the BET surface area, total pore volume and the adsorption capacity as compared to the original carbon. FTIR and Boehm's titration suggested that ITAC-Fe was characteristic of more acidic functional groups than ITAC. Adsorption of TC on both samples exhibited a strong pH-dependent behavior and adsorption capacity reduced rapidly with the increasing solution pH. The adsorption kinetics agreed well with the pseudo-second-order model and the adsorption isotherms data were well described by Langmuir model with the maximum adsorption capacity of 625.022 mg/g for ITAC and 769.231 mg/g for ITAC-Fe. The present work suggested that ITAC-Fe could be used to remove tetracycline effectively from aqueous solutions. PMID:24021870

Li, Gang; Zhang, Dongsheng; Wang, Man; Huang, Ji; Huang, Lihui

2013-12-01

53

Measurements of Al(NO{sub 3}){sub 3} activities in aqueous nitrate solutions  

SciTech Connect

Aluminum nitrate activity coefficient obtained by vapor pressure osmometry are compared with activity coefficients derived from nitric acid extraction measurements using Bromley`s correlation. This solvent extraction approach was possible because of the poor extraction of Al{sup 3+}(D{sub Al} {le} 10{sup {minus}3}) by the chosen solvents. The solvent compositions were 0.25M CMPO (octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide) in tetrachloroethylene (TCE) and 0.25M CMPO with 0.75M tributyle phosphate (TBP) in TCE. In both approaches, nitric acid was used to supress the hydrolysis of Al{sup 3+}. At high ionic strengths, the two techniques yielded very similar activity coefficients for Al(NO{sub 3}){sub 3}. However, at intermediate and very low ionic strengths, the two procedures produced activity coefficients which differed considerably from each other. 2 figures, 3 tables, 18 references.

Chaiko, D.J.; Fredrickson, D.R.; Difilippo, A.A.; Smidt, S.M.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Tasker, I.R. [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States)

1992-09-01

54

Measurements of Al(NO sub 3 ) sub 3 activities in aqueous nitrate solutions  

SciTech Connect

Aluminum nitrate activity coefficient obtained by vapor pressure osmometry are compared with activity coefficients derived from nitric acid extraction measurements using Bromley's correlation. This solvent extraction approach was possible because of the poor extraction of Al{sup 3+}(D{sub Al} {le} 10{sup {minus}3}) by the chosen solvents. The solvent compositions were 0.25M CMPO (octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide) in tetrachloroethylene (TCE) and 0.25M CMPO with 0.75M tributyle phosphate (TBP) in TCE. In both approaches, nitric acid was used to supress the hydrolysis of Al{sup 3+}. At high ionic strengths, the two techniques yielded very similar activity coefficients for Al(NO{sub 3}){sub 3}. However, at intermediate and very low ionic strengths, the two procedures produced activity coefficients which differed considerably from each other. 2 figures, 3 tables, 18 references.

Chaiko, D.J.; Fredrickson, D.R.; Difilippo, A.A.; Smidt, S.M.; Vandegrift, G.F. (Argonne National Lab., IL (United States)); Tasker, I.R. (National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States))

1992-01-01

55

Water activities, densities, and refractive indices of aqueous sulfates and sodium nitrate droplets of atmospheric importance  

NASA Astrophysics Data System (ADS)

Water activities, densities, and refractive indices over extended concentration ranges at 25°C are reported for solution droplets containing a single salt of either (NH4)2SO4, NH4HSO4, (NH4)3H(SO4)2, Na2SO4, NaHSO4, or NaNO3, which are common constituents of atmospheric aerosols. The extensive data reported here are obtained from experiments using the single-particle levitation technique recently developed for measuring the thermodynamic and optical properties of microdroplets. These data should find application in mathematical models predicting the dynamic behavior, visibility reduction, and radiative effects of atmospheric sulfate and nitrate aerosols.

Tang, I. N.; Munkelwitz, H. R.

1994-09-01

56

Hydrodynamic and electro-osmotic studies of some aqueous nitrate salt solutions through a porous membrane  

NASA Astrophysics Data System (ADS)

The authors have taken measurements on hydrodynamic and electro- osmotic permeation of water and aqueous salt solutions of ?, ?, and ? in the concentration range ? M to ? M, across pyrex-sintered glass membrane (G-3). The data obtained were used to ascertain the form of transport equation using the theory of non-equilibrium thermodynamics. Phenomenological coefficients, average pore radius, number of pores, and membrane constant have been evaluated. Zeta potential values have been evaluated to characterize the electrical nature of the membrane-permeant interface.

Kumar, Manoj; Ram, Bali

2013-12-01

57

Hollow fiber supported liquid membrane: a novel technique for separation and recovery of plutonium from aqueous acidic wastes  

Microsoft Academic Search

Low plutonium content acidic waste is generated in nuclear chemical facilities. Study was initiated to develop hollow fiber supported liquid membrane (HFSLM) technique for quantitative separation and recovery of plutonium (Pu) from such wastes using tri-n-butyle phosphate (TBP) in dodecane as carrier. Hollow fiber test module was fabricated using 20 lumens of 33.91cm2 surface area and 9cm length. After satisfactory

N. S Rathore; J. V Sonawane; Anil Kumar; A. K Venugopalan; R. K Singh; D. D Bajpai; J. P Shukla

2001-01-01

58

Studies on Nylon-66 membrane using aqueous solutions of potassium and lead nitrate salts as permeants  

NASA Astrophysics Data System (ADS)

Measurements on hydrodynamic and electro-osmotic permeability of water and aqueous solutions of KNO3 and Pb(NO3)2 in the concentration (C) range of 10 -4 10^{-4} M to 10 -3 10^{-3} M are made across the Nylon-66 membrane. The data obtained are used to ascertain the form of transport equation using the theory of non-equilibrium thermodynamics. Conductance of membrane equilibrated with water and aqueous solutions are measured and the data are used to estimate phenomenological coefficients. These phenomenological coefficients are used to determine the average pore radius, the average number of pores and the membrane constant. Zeta potentials are evaluated using electro-osmotic permeability and membrane-permeant conductance data to understand the electrical nature of the membrane-permeant interface. It is observed that hydrodynamic permeability and electro-osmotic permeability depend linearly on the applied pressure difference and the potential difference, respectively.

Kumar, Manoj; Ram, Bali

2015-03-01

59

THE MECHANISM OF MASS TRANSFER OF SOLUTES ACROSS LIQUID-LIQUID INTERFACES. III. THE TRANSFER OF URANYL NITRATE BETWEEN SOLVENT AND AQUEOUS PHASES  

Microsoft Academic Search

Over-all transfer coefficients were determined for the transfer of ; uranyl nitrate between water and the three solvents dibutoxy diethyl ether ; (D.B.C.), methyl iso-butyl ketone (hexone), and a 20 per cent solution of tri n-; butyl phosphate (T.B.P.) in odorless kerosene (O.K.), benzene, or carbon ; tetrachloride. In some experiments with D.B.C. the aqueous phase was 3N nitric ;

J Lewis

1958-01-01

60

Infrared optical constants of aqueous sulfate nitrate ammonium multi-component tropospheric aerosols from attenuated total reflectance measurements—Part I: Results and analysis of spectral absorbing features  

NASA Astrophysics Data System (ADS)

In this paper, the first part of two, we present new high-spectral-resolution infrared (IR) optical constants for multi-component aqueous solutions composed of ammonium sulfate, ammonium nitrate, sulfuric acid and nitric acid over a range of compositions and temperatures representative of tropospheric conditions and atmospheric aerosols. The optical constants were determined from ATR measurements via a Kramers Kronig transformation. To accomplish this, we adapted an existing technique for estimating the real index of refraction of aqueous sulfate and nitrate solutions at multiple visible frequencies as a function of concentration and temperature. An approximation of the low-frequency behavior of the ATR spectrum was also used to reduce the error associated with using ATR data of finite frequency range. This paper also provides a brief examination of absorption spectra for analyzed mixtures in relation to their composition and temperature and discusses possible implications. The new optical constants will be of great utility to high-spectral-resolution IR remote sensing as well as radiative balance analysis in climate studies because they will enable researchers for the first time to model the impacts of tropospheric aqueous sulfate nitrate ammonium multi-component aerosols, including their mixtures with other important species such as dust or soot.

Boer, Gregory J.; Sokolik, Irina N.; Martin, Scot T.

2007-11-01

61

Heavy-metal-induced Inhibition of Aspergillus niger nitrate reductase: Applications for Rapid Contaminant Detection in Aqueous Samples  

SciTech Connect

Enzyme inhibition assays have the potential to rapidly screen and identify heavy metals in environmental samples. Inhibition of nitrate reductase (NR) was examined as a method for detecting toxic metals. The activity of NR (EC 1.6.6.2) from Aspergillus niger was assayed as a function of metal concentration in the presence of Cd2+, Cr3+, Cr6+, Cu2+, Ni2+, Pb2+, and Zn2+. NR exhibited sensitivity to these metals at concentrations below 10 µM. Various buffers were screened for their ability to protect NR activity from metal inhibition, and 3-(N-morpholino) propanesulfonic acid (MOPS) was selected as the buffering system for the NR assays as it exhibited the least interference with metal inhibition, thus providing increased assay sensitivity. The hypothesis that chelating agents could prevent the inhibition of NR activity by metal ions was also tested. Results indicated that 10 mM ethylenediaminetetraacetic acid (EDTA) could protect NR activity from inhibition by Cr3+, Cu2+, Cd2+, Ni2+, and Zn2+ at concentrations below 100 µM, but that the EDTA had no effect on NR inhibition by Cr6+. An amount of 10 mM nitrilotriacetic acid (NTA) prevented NR inhibition by Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+ at metal concentrations below 100 µM. However, 10 mM NTA was unable to protect the enzyme from inhibition by either Cr3+ or Cr6+. These results indicated that through specific metal chelation, a NR-based method for individually quantifying Cr3+ and Cr6+ species in aqueous solutions could be developed. The ability to restore activity to NR which been previously inhibited by exposure to 100 µM Pb2+, Cd2+, Zn2+, Cu2+, and Cr3+ was explored to determine whether NR activity could be recovered by EDTA additions for use in consecutive metal inhibition assays. The results showed NR activity could not be regained after exposure to Cr3+ or Cu2+, but did partially recover activity after Cd2+, Pb2+, and Zn2+ exposure.

Apel, William Arnold; Aiken, Abigail Marie; Peyton, Brent Michael; Petersen, James N.

2003-03-01

62

Solvent extraction system for plutonium colloids and other oxide nano-particles  

SciTech Connect

The invention provides a method for extracting plutonium from spent nuclear fuel, the method comprising supplying plutonium in a first aqueous phase; contacting the plutonium aqueous phase with a mixture of a dielectric and a moiety having a first acidity so as to allow the plutonium to substantially extract into the mixture; and contacting the extracted plutonium with second a aqueous phase, wherein the second aqueous phase has a second acidity higher than the first acidity, so as to allow the extracted plutonium to extract into the second aqueous phase. The invented method facilitates isolation of plutonium polymer without the formation of crud or unwanted emulsions.

Soderholm, Lynda; Wilson, Richard E; Chiarizia, Renato; Skanthakumar, Suntharalingam

2014-06-03

63

Plutonium adsorption by selected inorganic compounds  

Microsoft Academic Search

Plutonium may be removed from aqueous solution by adsorption on inorganic materials. Hydroxylapatite, dibasic and tribasic calcium phosphate, calcium cyanamide, and sodium titanate are particularly noteworthy for their ability to concentrate plutonium. The extent of adsorption and pH of maximum adsorption depend upon the chemical form of the dissolved plutonium.

1980-01-01

64

Plutonium adsorption by selected inorganic compounds  

SciTech Connect

Plutonium may be removed from aqueous solution by adsorption on inorganic materials. Hydroxylapatite, dibasic and tribasic calcium phosphate, calcium cyanamide, and sodium titanate are particularly noteworthy for their ability to concentrate plutonium. The extent of adsorption and pH of maximum adsorption depend upon the chemical form of the dissolved plutonium.

Silver, G.L.

1980-10-10

65

Preparation of Uranium and Plutonium Metals  

Microsoft Academic Search

A new process for preparing uranium and plutonium metals has been developed. The process is based on the high extractability of the elements with sodium amalgam from aqueous solutions. After extracting the uranium or plutonium with sodium amalgam, the resulting amalgam was heated in vacuum so that mercury and sodium were separated to produce uranium or plutonium metal. The mercury

Yoshii KOBAYASHI; Akira SAITO

1975-01-01

66

Size effect of hematite and corundum inclusions on the efflorescence relative humidities of aqueous ammonium nitrate particles  

E-print Network

on the generation and the manipulation of aerosols containing particles composed of ammonium sulfate coatings that significantly decreases the critical supersaturation necessary to crystallize ammonium sulfate [Han and Martin ammonium nitrate particles Jeong-Ho Han Department of Environmental Chemistry, Atmospheric Science Division

67

17. VIEW OF THE FIRST PLUTONIUM BUTTON PRODUCED FROM THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. VIEW OF THE FIRST PLUTONIUM BUTTON PRODUCED FROM THE BUILDING 371 AQUEOUS RECOVERY OPERATION. (9/30/83) - Rocky Flats Plant, Plutonium Recovery Facility, Northwest portion of Rocky Flats Plant, Golden, Jefferson County, CO

68

Subchronic inhalation of carbon tetrachloride alters the tissue retention of acutely inhaled plutonium-239 nitrate in F344 rats and syrian golden hamsters  

SciTech Connect

Carbon tetrachloride (CCl{sub 4}) has been used extensively in the nuclear weapons industry, so it is likely that nuclear plant workers have been exposed to both CCl{sub 4} and plutonium compounds. Future exposures may occur during {open_quotes}cleanup{close_quotes} operations at weapons productions sites such as the Hanford, Washington, and Rocky Flats, Colorado, facilities. Inhalation of 20 and 100 ppm CCl{sub 4} by hamsters reduces uptake of {sup 239}Pu solubilized from lung, shunting the {sup 239}Pu to the skeleton.

Benson, J.M.; Barr, E.B.; Lundgren, D.L. [and others

1995-12-01

69

Thermochemical nitrate destruction  

DOEpatents

A method is disclosed for denitrification of nitrates and nitrates present in aqueous waste streams. The method comprises the steps of (1) identifying the concentration nitrates and nitrites present in a waste stream, (2) causing formate to be present in the waste stream, (3) heating the mixture to a predetermined reaction temperature from about 200.degree. C. to about 600.degree. C., and (4) holding the mixture and accumulating products at heated and pressurized conditions for a residence time, thereby resulting in nitrogen and carbon dioxide gas, and hydroxides, and reducing the level of nitrates and nitrites to below drinking water standards.

Cox, John L. (Richland, WA); Hallen, Richard T. (Richland, WA); Lilga, Michael A. (Richland, WA)

1992-01-01

70

Isothermal decomposition of hydroxylamine and hydroxylamine nitrate in aqueous solutions in the temperature range 80-160 degrees C.  

PubMed

Hydroxylamine (HA) and hydroxylamine nitrate (HAN) have been involved independently in several tragic accidents, which incurred numerous fatalities and injuries. Following these incidents, adiabatic calorimetry and computational chemistry research was conducted on those compounds, suggesting potential reaction pathways of their decomposition, but the mechanism of their unstable behavior, still have not been completely understood. In the present work, isothermal decomposition tests were performed accompanied with HPLC, ion chromatography and UV analyses in the temperature range 80-160 degrees C. Condition-dependent autocatalytic decompositions were demonstrated for HA and HAN, and an intermediate formation has been observed that is most likely responsible for their autocatalytic behavior. These findings corroborate previously reported computational chemistry results. PMID:19027229

Liu, Lijun; Papadaki, Maria; Pontiki, Eleni; Stathi, Panagiota; Rogers, William J; Mannan, M Sam

2009-06-15

71

Vapour pressures of saturated aqueous solutions of ammonium iodide, potassium iodide, potassium nitrate, strontium chloride, lithium sulphate, sodium thiosulphate, magnesium nitrate, and uranyl nitrate from T =(278 to 323) K  

Microsoft Academic Search

Vapour pressures of saturated aqueous solutions of NH4I, KI, KNO3, SrCl2, Li2SO4, Na2S2O3, Mg(NO3)2, and UO2(NO3)2were determined in the temperature range (278 to 323) K using an electronic hygrometer with an electrolyte sensor, and compared with literature data. Water activities, osmotic coefficients, and molar enthalpies of vaporization and solution at saturation point were evaluated from the determined vapour pressures.

Alexander Apelblat; Eli Korin

1998-01-01

72

Polymerization of Pu(IV) in aqueous nitric acid solutions  

SciTech Connect

The polymerization of Pu(IV) in aqueous nitric acid solutions has been studied spectrophotometrically both to establish the influence of large UO{sub 2}(NO{sub 3}){sub 2} concentrations on the polymerization rates and, more generally, to review the influence of the major parameters on the polymer reaction. Typically, experiments have been performed at 50{sup 0}C and with 0.05 M Pu in nitric acid solutions that vary in acidity from 0.07 to 0.4 M. An induction period usually precedes the polymer growth stage during which time nucleation of primary hydrolysis products occurs. Uranyl nitrate retards the polymerization reaction by approximately 35% in spite of the counteracting influence of the nitrate ions associated with this solute. The rate of polymer formation, expressed as d(percent polymer)/dt, has been shown to depend on the total plutonium concentration in reactions where the Pu(IV) concentration remained constant; and it is therefore suggested that the polymer reaction rate is not first order with respect to the concentration of plutonium as was previously thought. It has been shown further that accurate acid determinations on stock reagents are essential in order to obtain reliable polymerization experiments. Satisfactory procedures for these analyses did not exist, so appropriate modifications to the iodate precipitation methods were developed. The most ideal plutonium reagent material has been shown to be crystalline Pu(IV) nitrate because it can be added directly to acid solutions without the occurrence of unintentional hydrolysis reactions.

Toth, L.M.; Friedman, H.A.; Osborne, M.M.

1980-10-01

73

Radiolytic effects of plutonium.  

SciTech Connect

Plutonium isotopes, most of them a-emitters, cause radiolytic changes in the matrix, in whic h they are embedded. The internal irradiation of Pu metal or its alloys results in physical changes, largel y as a result of the formation of helium bubbles, well-known to material scientists and weapons specialists . In all other media where plutonium occurs, usually as Pu'+ in an ionic form, the results of irradiation ar e chemical in nature. Homogenous media containing Pu, are often aqueous or non-aqueous solutions o f plutonium compounds, mostly originating during processing of spent nuclear fuel or from Pu processing . Heterogenous matrices containing plutonium are more complex from the point of view of radiolysis; they usually contain a variety of combinations of common materials contaminated with radionuclides . This class of radioactive materials represents a challenge for the management of plutonium waste . One has to consider a range of time scales for radiolytic effects (and consequently a several orders o f magnitude range of the cumulative dose) beginning with waste generation, through packaging, transportation, to the period of final storage . Final storage could be for thousands of years in deep geologic repositories . At every ' stage of that time scale, radiolysis proceeds continuously an d cumulative effects c an complicate operating procedures and final disposition . The results presented here have been obtained from experiments that have irradiated of model materials, which are typically the objects of contamination with plutonium . They were irradiated with linearly accelerated electrons up to very high dose rates, adjusted to simulate any contamination at any point on the time scale .

Zagorski, Z. (Zbigniew); Dziewinski, J. J. (Jacek J.); Conca, James L.

2003-01-01

74

Purge-assisted headspace solid-phase microextraction combined with gas chromatography/mass spectrometry for the determination of trace nitrated polycyclic aromatic hydrocarbons in aqueous samples.  

PubMed

This study describes a new procedure, namely, purge-assisted headspace solid phase microextraction combined with gas chromatography/negative ion chemical ionization mass spectrometry (PA/HS-SPME-GC/NICI-MS), which is used to determine seven nitrated polycyclic aromatic hydrocarbons (NPAHs) in aqueous samples. High extraction efficiency was obtained with PA/HS-SPME with polydimethylsiloxane (PDMS) fiber coating. A programmable temperature vaporizing (PTV) inlet was used in the desorption process. Selected ion monitoring (SIM) was used for quantitative and qualitative purposes. The linear range of detection of the proposed method was 5-5000 pg/mL with coefficients of determination between 0.995 and 0.999. Limits of detection (LODs) for seven NPAHs were 0.01-0.06 pg/mL. The relative standard deviation was below 12.7% at a concentration of 50 pg/mL. Compared with headspace-solid phase microextraction (HS-SPME), the purge procedure enhanced the extraction efficiency for high boiling point analytes, such as 7-nitrobenz[a]anthracene (7-NBA) and 6-nitrochrysene (6-NC). The proposed method provides a sensitive method for NPAH analysis at the pg/mL level. The application of the proposed method for the determination of trace NPAHs in real samples was investigated by analyzing aqueous samples from rivers. The concentrations of NPAHs detected from the samples ranged from 5.2 to 7.5 pg/mL. This method was applied successfully in the analysis of trace NPAHs in river samples. PMID:23089518

Hung, Cheng-Han; Ho, Hsin-Pin; Lin, Mei-Tzu; Chen, Chung-Yu; Shu, Youn-Yuen; Lee, Maw-Rong

2012-11-23

75

LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY  

SciTech Connect

A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

Nash, C.

2012-02-03

76

Purification of alkali metal nitrates  

DOEpatents

A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

Fiorucci, Louis C. (Hamden, CT); Gregory, Kevin M. (Woodridge, IL)

1985-05-14

77

PRECIPITATION AND HYDROLYSIS OF THORIUM(IV) IN AQUEOUS SOLUTION. II. INFLUENCE OF pH AND NEUTRAL ELECTROLYTES UPON THE PRECIPITATION IN THE SYSTEM THORIUM NITRATE-POTASSIUM PHTHALATE  

Microsoft Academic Search

The influence of the pH and other neutral electrolytes upon the ; precipitation and hydrolysis of thorium(IV) in aqueous solutions of thorium ; nitrate and potassium phthalate was investigated. A three-dimensional ; concentration tyndallogram in which turbidity has been plotted against the ; concentration of potassium phthalate and the pH, at constant concentration of ; Th(IV) 1.25 x 10⁻³ M,

H. Bilinski; H. Fueredi; B. Tezak

1963-01-01

78

Removal of americium from aqueous nitrate solutions by sorption onto PC88A-impregnated macroporous polymeric beads.  

PubMed

The removal of Am (III) ions from aqueous solutions was studied by solid-liquid extraction using indigenously synthesized Extractant Impregnated Macroporous Polymeric Beads (EIMPBs). These beads were prepared by an in situ phase inversion method using polyethersulfone (PES) as base polymer and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) as an extractant. The synthesized EIMPBs were characterized by FTIR, TGA and SEM techniques. The batch equilibration study using these beads for the uptake of Am (III) was carried out as a function of parameters, like pH, equilibration time, Am (III) concentration, etc. The blank polymeric beads, without PC88A, have shown negligible sorption of Am (III) under the experimental conditions. The experimental data on the sorption behavior of Am (III) on the polymeric beads fitted well in the pseudo-second-order kinetics model. The synthesized polymeric beads exhibited very good sorption capacity for Am (III) at pH 3. The reusability of the beads was also ascertained by repetitive sorption/desorption of Am (III) up to 10 cycles of operation, without any significant change in their sorption characteristics. PMID:24997262

Pathak, S K; Tripathi, S C; Singh, K K; Mahtele, A K; Kumar, Manmohan; Gandhi, P M

2014-08-15

79

Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles.  

PubMed

Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ? 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity. PMID:24999115

Su, Yiming; Adeleye, Adeyemi S; Huang, Yuxiong; Sun, Xiaoya; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei; Keller, Arturo A

2014-10-15

80

Plutonium aging  

SciTech Connect

The author describes the plutonium aging program at the Los Alamos National Laboratory. The aging of plutonium components in the US nuclear weapons stockpile has become a concern due to several events: the end of the cold war, the cessation of full scale underground nuclear testing as a result of the Comprehensive Test Ban Treaty (CTBT) and the closure of the Rocky Flats Plant--the site where the plutonium components were manufactured. As a result, service lifetimes for nuclear weapons have been lengthened. Dr. Olivas will present a brief primer on the metallurgy of plutonium, and will then describe the technical approach to ascertaining the long-term changes that may be attributable to self-radiation damage. Facilities and experimental techniques which are in use to study aging will be described. Some preliminary results will also be presented.

Olivas, J.D.

1999-03-01

81

LABORATORY INVESTIGATIONS OF INTERACTIONS OF IRRADIATED O-XYLENE/NOX/SO2/AIR MIXTURES WITH AQUEOUS MEDIA CONTAINING SODIUM FLUORIDE, SODIUM TRIFLUOROACETATE, AMMONIUM NITRATE AND HYDROGEN PEROXIDE  

EPA Science Inventory

Laboratory experiments were conducted to investigate interactions between complex air mixtures and aqueous films containing hydrolysis products of hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) oxidation products. he experiments consisted of exposing aqueous films con...

82

Thermal Stability Studies of Candidate Decontamination Agents for Hanford’s Plutonium Finishing Plant Plutonium-Contaminated Gloveboxes  

SciTech Connect

This report provides the results of PNNL's and Fluor's studies of the thermal stabilities of potential wastes arising from decontamination of Hanford's Plutonium Finishing Plant's plutonium contaminated gloveboxes. The candidate wastes arising from the decontamination technologies ceric nitrate/nitric acid, RadPro, Glygel, and Aspigel.

Scheele, Randall D.; Cooper, Thurman D.; Jones, Susan A.; Ewalt, John R.; Compton, James A.; Trent, Donald S.; Edwards, Matthew K.; Kozelisky, Anne E.; Scott, Paul A.; Minette, Michael J.

2005-09-29

83

Nitrate Protocol  

NSDL National Science Digital Library

The purpose of this resource is to measure the nitrate-nitrogen of water. Students will use a nitrate kit to measure the nitrate-nitrogen in the water at their hydrology site. The exact procedure depends on the instructions in the nitrate kit used.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

84

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.  

Code of Federal Regulations, 2010 CFR

... true Silver nitrate and hydrogen peroxide solution. 172.167 Section...172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution...mixture of silver nitrate and hydrogen peroxide may be safely used in...

2010-04-01

85

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.  

Code of Federal Regulations, 2011 CFR

... false Silver nitrate and hydrogen peroxide solution. 172.167 Section...172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution...mixture of silver nitrate and hydrogen peroxide may be safely used in...

2011-04-01

86

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.  

Code of Federal Regulations, 2014 CFR

... false Silver nitrate and hydrogen peroxide solution. 172.167 Section...172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution...mixture of silver nitrate and hydrogen peroxide may be safely used in...

2014-04-01

87

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.  

Code of Federal Regulations, 2012 CFR

... false Silver nitrate and hydrogen peroxide solution. 172.167 Section...172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution...mixture of silver nitrate and hydrogen peroxide may be safely used in...

2012-04-01

88

21 CFR 172.167 - Silver nitrate and hydrogen peroxide solution.  

Code of Federal Regulations, 2013 CFR

... false Silver nitrate and hydrogen peroxide solution. 172.167 Section...172.167 Silver nitrate and hydrogen peroxide solution. An aqueous solution...mixture of silver nitrate and hydrogen peroxide may be safely used in...

2013-04-01

89

Nitrate reduction  

DOEpatents

Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

Dziewinski, Jacek J. (Los Alamos, NM); Marczak, Stanislaw (Los Alamos, NM)

2000-01-01

90

Nitrate and periplasmic nitrate reductases  

PubMed Central

The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types – periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed. PMID:24141308

Sparacino-Watkins, Courtney; Stolz, John F.; Basu, Partha

2014-01-01

91

Plutonium story  

SciTech Connect

The first nuclear synthesis and identification (i.e., the discovery) of the synthetic transuranium element plutonium (isotope /sup 238/Pu) and the demonstration of its fissionability with slow neutrons (isotope /sup 239/Pu) took place at the University of California, Berkeley, through the use of the 60-inch and 37-inch cyclotrons, in late 1940 and early 1941. This led to the development of industrial scale methods in secret work centered at the University of Chicago's Metallurgical Laboratory and the application of these methods to industrial scale production, at manufacturing plants in Tennessee and Washington, during the World War II years 1942 to 1945. The chemical properties of plutonium, needed to devise the procedures for its industrial scale production, were studied by tracer and ultramicrochemical methods during this period on an extraordinarily urgent basis. This work, and subsequent investigations on a worldwide basis, have made the properties of plutonium very well known. Its well studied electronic structure and chemical properties give it a very interesting position in the actinide series of inner transition elements.

Seaborg, G T

1981-09-01

92

Theoretical study of the structural properties of plutonium(IV) and (VI) complexes.  

PubMed

The structural properties of several plutonium(IV) and (VI) complexes have been examined in the gaseous and aqueous phases using Kohn-Sham density functional theory calculations with scalar relativistic effective core potentials and the polarizable continuum solvation model. The aquo and nitrate complexes of PuO(2)(2+) and Pu(4+) were considered in addition to the aquo-chloro complexes of PuO(2)(2+). The nitrate and chloro- complexes formed with triphenylphosphine oxide (TPPO) and tributylphosphate (TBP) respectively were also studied. The structural parameters of the plutonyl complexes were compared to their uranyl and neptunyl analogues. The bond lengths and vibrational frequencies of the plutonyl complexes can generally be computed with sufficient accuracy with the pure PBE density functional with shorter bond lengths being predicted by the B3LYP functional. The structural parameters of the [PuO(2)Cl(2)L(2)] systems formed with TPPO and TBP as well as the aqueous [PuO(2)Cl(2)(H(2)O)(3)] complex are matched to previous experimental results. Overall, the inclusion of ligands in the equatorial region results in significant changes in the stretching frequency of the plutonyl group. The structural features of the plutonyl (VI) systems are rather similar to those of their 5f(0) uranyl and 5f(1) neptunyl counterparts. For the Pu(IV) aquo and nitrate complexes, the average of the calculated Pu-OH(2) and Pu-O(nitrate) bond lengths are generally within 0.04 Å of the reported experimental values. Overall Kohn-Sham DFT can be used successfully in predicting the structures of this diverse set of Pu(VI) and Pu(IV) complexes. PMID:22040181

Odoh, Samuel O; Schreckenbach, Georg

2011-12-01

93

Seaborg's Plutonium ?  

E-print Network

Passive x-ray and gamma-ray analysis was performed on UC Berkeley's EH&S Sample S338. The object was found to contain Pu-239 and no other radioactive isotopes. The mass of Pu-239 contained in this object was determined to be 2.0 +- 0.3 micrograms. These observations are consistent with the identification of this object being the 2.77-microgram plutonium oxide sample described by Glenn Seaborg and his collaborators as the first sample of Pu-239 that was large enough to be weighed.

Norman, Eric B; Telhami, Kristina E

2014-01-01

94

Seaborg's Plutonium?  

E-print Network

Passive x-ray and gamma-ray analysis was performed on UC Berkeley's EH&S Sample S338. The object was found to contain Pu-239 and no other radioactive isotopes. The mass of Pu-239 contained in this object was determined to be 2.0 +- 0.3 micrograms. These observations are consistent with the identification of this object being the 2.77-microgram plutonium oxide sample described by Glenn Seaborg and his collaborators as the first sample of Pu-239 that was large enough to be weighed.

Eric B. Norman; Keenan J. Thomas; Kristina E. Telhami

2015-02-17

95

Processing of Non-PFP Plutonium Oxide in Hanford Plants  

SciTech Connect

Processing of non-irradiated plutonium oxide, PuO2, scrap for recovery of plutonium values occurred routinely at Hanford’s Plutonium Finishing Plant (PFP) in glovebox line operations. Plutonium oxide is difficult to dissolve, particularly if it has been high-fired; i.e., calcined to temperatures above about 400°C and much of it was. Dissolution of the PuO2 in the scrap typically was performed in PFP’s Miscellaneous Treatment line using nitric acid (HNO3) containing some source of fluoride ion, F-, such as hydrofluoric acid (HF), sodium fluoride (NaF), or calcium fluoride (CaF2). The HNO3 concentration generally was 6 M or higher whereas the fluoride concentration was ~0.5 M or lower. At higher fluoride concentrations, plutonium fluoride (PuF4) would precipitate, thus limiting the plutonium dissolution. Some plutonium-bearing scrap also contained PuF4 and thus required no added fluoride. Once the plutonium scrap was dissolved, the excess fluoride was complexed with aluminum ion, Al3+, added as aluminum nitrate, Al(NO3)3•9H2O, to limit collateral damage to the process equipment by the corrosive fluoride. Aluminum nitrate also was added in low quantities in processing PuF4.

Jones, Susan A.; Delegard, Calvin H.

2011-03-10

96

A biological source of oceanic alkyl nitrates  

NASA Astrophysics Data System (ADS)

Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

2013-12-01

97

Aqueous complexation of thorium(IV), uranium(IV), neptunium(IV), plutonium(III/IV), and cerium(III/IV) with DTPA.  

PubMed

Aqueous complexation of Th(IV), U(IV), Np(IV), Pu(III/IV), and Ce(III/IV) with DTPA was studied by potentiometry, absorption spectrophotometry, and cyclic voltammetry at 1 M ionic strength and 25 °C. The stability constants for the 1:1 complex of each trivalent and tetravalent metal were calculated. From the potentiometric data, we report stability constant values for Ce(III)DTPA, Ce(III)HDTPA, and Th(IV)DTPA of log ?(101) = 20.01 ± 0.02, log ?(111) = 22.0 ± 0.2, and log ?(101) = 29.6 ± 1, respectively. From the absorption spectrophotometry data, we report stability constant values for U(IV)DTPA, Np(IV)DTPA, and Pu(IV)DTPA of log ?(101) = 31.8 ± 0.1, 32.3 ± 0.1, and 33.67 ± 0.02, respectively. From the cyclic voltammetry data, we report stability constant values for Ce(IV) and Pu(III) of log ?(101) = 34.04 ± 0.04 and 20.58 ± 0.04, respectively. The values obtained in this work are compared and discussed with respect to the ionic radius of each cationic metal. PMID:22738207

Brown, M Alex; Paulenova, Alena; Gelis, Artem V

2012-07-16

98

Method for aqueous radioactive waste treatment  

DOEpatents

Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions. 3 figures.

Bray, L.A.; Burger, L.L.

1994-03-29

99

Method for aqueous radioactive waste treatment  

DOEpatents

Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions.

Bray, Lane A. (Richland, WA); Burger, Leland L. (Richland, WA)

1994-01-01

100

Method for dissolving delta-phase plutonium  

DOEpatents

A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.

Karraker, David G. (1600 Sherwood Pl., SE., Aiken, SC 29801)

1992-01-01

101

Dehydration of plutonium or neptunium trichloride hydrate  

DOEpatents

A process is described for preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride.

Foropoulos, J. Jr.; Avens, L.R.; Trujillo, E.A.

1992-03-24

102

Dehydration of plutonium or neptunium trichloride hydrate  

DOEpatents

A process of preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride is provided.

Foropoulos, Jr., Jerry (Los Alamos, NM); Avens, Larry R. (Los Alamos, NM); Trujillo, Eddie A. (Espanola, NM)

1992-01-01

103

Photoinduced degradation of orange II on different iron (hydr)oxides in aqueous suspension: rate enhancement on addition of hydrogen peroxide, silver nitrate, and sodium fluoride.  

PubMed

Photoinduced organic oxidation with iron (hydr)oxides in aqueous suspension has been argued with respect to two principal mechanisms: (a) photoinduced ligand-to-metal charge transfer within a surface complex and (b) semiconductor photocatalysis. In this work, the photodegradation of azo dye orange II with UV light (lambda > or = 320 nm) in the aerated aqueous suspensions of haematite, maghemite, magnetite, goethite, lepidocrocite, and feroxyhite at an initial pH of 6.5 has been examined. The results showed that (1) all of the catalysts were effective at initiating dye photodegradation but the iron oxides appeared to be more active than the iron hydroxides; (2) the photodissolution of different iron phases and the dye photolysis in the dissolved iron solutions were very slow; (3) the initial rate of dye loss was proportional to the initial amount of adsorption, implying dye photodegradation on the catalyst surface; and (4) upon addition of H2O2, AgNO3, and NaF to the suspension, the rate of dye photodegradation was significantly enhanced with all the catalysts. In the presence of H2O2, less than 50% of the total rate enhancement was ascribed to the photo-Fenton reaction in solution and the dark Fenton reactions in solution and on the catalyst. In the presence of AgNO3, about 1 mole of silver particles was produced by consuming 3 moles of the dye substrate. In the presence of NaF, hydroxyl radicals were detected by an ethanol scavenger, whereas such radicals were not found in the absence of NaF. Moreover, under visible-light irradiation (lambda > or = 450 nm), the dye degradation was much slower than that under UV irradiation, but the reaction was also accelerated by the addition of NaF and AgNO3. The results suggest that mechanism b, not mechanism a, is operative for dye photodegradation occurring on the iron (hydr)oxides. A detailed discussion of all possible pathways is given in the text. PMID:18052220

Du, Weiping; Xu, Yiming; Wang, Yansong

2008-01-01

104

Standard test method for plutonium by Iron (II)/Chromium (VI) amperometric titration  

E-print Network

1.1 This test method covers the determination of plutonium in unirradiated nuclear-grade plutonium dioxide, uranium-plutonium mixed oxides with uranium (U)/plutonium (Pu) ratios up to 21, plutonium metal, and plutonium nitrate solutions. Optimum quantities of plutonium to measure are 7 to 15 mg. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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.

American Society for Testing and Materials. Philadelphia

2002-01-01

105

THE MICROSTRUCTURE OF PLUTONIUM DIOXIDE PREPARED BY VARIOUS METHODS  

Microsoft Academic Search

The microstructure of plutonium dioxide prepared from the nitrate, ; iodate, suliate, hydroxide, and oxalate was examined. The preparation route has ; a marked influence on physical characteristics, especially on particle size ; distribution surface area and density. The sulfate gives a powder of low ; particle porositv and marked resistance to crystallite growth at higher ; temperatures. The powder

K. E. Francis; R. G. Sowden

1959-01-01

106

History and stabilization of the Plutonium Finishing Plant (PFP) complex, Hanford Site  

SciTech Connect

The 231-Z Isolation Building or Plutonium Metallurgy Building is located in the Hanford Site`s 200 West Area, approximately 300 yards north of the Plutonium Finishing Plant (PFP) (234-5 Building). When the Hanford Engineer Works (HEW) built it in 1944 to contain the final step for processing plutonium, it was called the Isolation Building. At that time, HEW used a bismuth phosphate radiochemical separations process to make `AT solution,` which was then dried and shipped to Los Alamos, New Mexico. (AT solution is a code name used during World War II for the final HEW product.) The process was carried out first in T Plant and the 224-T Bulk Reduction Building and B Plant and the 224-B Bulk Reduction Building. The 224-T and -B processes produced a concentrated plutonium nitrate stream, which then was sent in 8-gallon batches to the 231-Z Building for final purification. In the 231-Z Building, the plutonium nitrate solution underwent peroxide `strikes` (additions of hydrogen peroxide to further separate the plutonium from its carrier solutions), to form the AT solution. The AT solution was dried and shipped to the Los Alamos Site, where it was made into metallic plutonium and then into weapons hemispheres.` The 231-Z Building began `hot` operations (operations using radioactive materials) with regular runs of plutonium nitrate on January 16, 1945.

Gerber, M.S., Fluor Daniel Hanford

1997-02-18

107

The efficacies of pure LICAM(C) and DTPA on the retention of plutonium-238 and americium-241 in rats after their inhalation as nitrate and intravenous injection as citrate.  

PubMed

The pure carboxylated catechoyl amide LICAM(C) and the calcium and zinc salts of diethylenetriaminepenta-acetic acid (DTPA), were tested for efficacy for removing 238Pu and 241Am from rats after inhalation of the nitrate or intravenous injection of the citrate. The results were compared with the efficacy of methylated LICAM(C) used in previous experiments. It was shown that: (1) after inhalation of 238Pu nitrate, DTPA was far superior to pure LICAM(C); (2) after intravenous injection of 238Pu citrate, the infusion of DTPA plus LICAM(C) was only marginally more effective than DTPA alone; and (3) after inhalation or intravenous injection of 238Pu plus 241Am, the efficacy of pure LICAM(C) was only marginally more effective than the methylated form and neither form was effective for the decorporation of 241Am. It was concluded that DTPA, at present, remains the chelating agent of choice for treating persons accidentally contaminated with transportable forms of Pu and Am. PMID:2571662

Stradling, G N; Stather, J W; Gray, S A; Moody, J C; Ellender, M; Hodgson, A; Volf, V; Taylor, D M; Wirth, P; Gaskin, P W

1989-10-01

108

Plutonium recovery at the Los Alamos Scientific Laboratory  

SciTech Connect

Research programs have led to the adoption of procedures for all phases of plutonium recovery and purification. This report discusses some of the many procedures required to recover and purify the plutonium contained in the residues generated by LASL research, process development, and production activities. The report also discusses general plant facilities, the liquid and gaseous effluents, and solid waste management practices at the New Plutonium Facility, TA-55. Many of the processes or operations are merely steps in preparing the feed for one of the purification systems. For example, the plutonium is currently removed from noncombustibles in the pickling operation with an HNO/sub 3/ leach. The HNO/sub 3/ leach solution is the product of this operation and is sent to one of the nitrate anion-exchange systems for concentration and purification.

Christensen, E.L.

1980-06-01

109

Solubility of plutonium and uranium in alkaline salt solutions  

SciTech Connect

The solubility of plutonium and uranium in alkaline salt solutions, which will be processed in the In-Tank Precipitation (ITP) process, was investigated to screen for significant factors and interactions among the factors comprising the salt solutions. The factors included in the study were hydroxide, nitrate, nitrite, aluminate, sulfate, carbonate, and temperature. Over the range of factor concentrations studied, the level of hydroxide in the solution is not sufficient alone to predict the resulting concentration of plutonium and uranium in the solution. Other constituents of the salt solution play an important role in determining the amount of plutonium and uranium in solution. Statistical models predicting the plutonium and uranium concentrations over the range of salt solutions investigated are provided.

Hobbs, D.T.; Edwards, T.B.; Fleischman, S.D.

1993-02-12

110

21 CFR 181.33 - Sodium nitrate and potassium nitrate.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

2011-04-01

111

21 CFR 181.33 - Sodium nitrate and potassium nitrate.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Sodium nitrate and potassium nitrate. 181.33 Section 181.33 ...Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions...

2010-04-01

112

Use of Gadolinium as a Primary Criticality Control in Disposing Waste Containing Plutonium at SRS  

SciTech Connect

Use of gadolinium as a neutron poison has been proposed for disposing of several metric tons of excess plutonium at the Savannah River Site (SRS). The plutonium will first be dissolved in nitric acid in small batches. Gadolinium nitrate will then be added to the plutonium nitrate solution. The Gd-poisoned plutonium solution will be neutralized and transferred to large under-ground tanks. The pH of small batches of neutralized plutonium solution will be adjusted prior to addition of the glass frit for eventual production as glass logs. The use of gadolinium as the neutron poison would minimize the number of glass logs generated from this disposition. The primary criticality safety concerns regarding the disposal process are: (1) maintaining neutron moderation under all processing conditions since gadolinium has a very large absorption cross section for thermal neutrons, (2) characteristics of plutonium and gadolinium precipitation during the neutralization process, (3) mixing characteristics of the precipitate to ensure that plutonium would remain homogeneously mixed with gadolinium, and (4) potential separation of plutonium and gadolinium during nitric and formic acids addition. A number of experiments were conducted at the Savannah River National Laboratory to study the behavior of plutonium and gadolinium at various stages of the disposition process.

Andrew, Vincent

2005-01-04

113

Differential pulse polarographic determination of nitrate in environmental materials.  

PubMed

Nitrate can be determined with reliable accuracy and sensitivity by differential pulse polarography utilizing the catalytic reaction between nitrate and uranyl ion in the presence of potassium sulphate. The differential pulse polarographic peak-height is proportional to nitrate concentration from 1 to 50 muM. The calculated detection limit for nitrate is 8 x 10(-7)M in pure aqueous solution. The method has been applied to determination of nitrate in fresh snow, and river waters and animal feeds. PMID:18963604

Hemmi, H; Hasebe, K; Ohzeki, K; Kambara, T

1984-05-01

114

North Korean Plutonium Production  

Microsoft Academic Search

In 1992, as part of its obligations under the Nuclear Non?Proliferation Treaty, North Korea declared that it had earlier separated abut 100 grams of plutonium from damaged fuel rods removed from a 25 megawatt?thermal (MWt) gas?graphite reactor at Yongbyon. The plutonium was separated at the nearby “Radiochemical Laboratory.” Separated plutonium is the raw ingredient for making nuclear weapons, but 100

David Albright

1994-01-01

115

Redox speciation of plutonium  

Microsoft Academic Search

Knowledge of the oxidation state distribution of plutonium in natural waters is necessary in modeling its behavior in environmental systems. The redox speciation of plutonium is complicated by such effects as hydrolysis, complexation, disproportionation, solubility, and redox interchange reactions. The insolubility of Pu(OH)4 is often the limiting factor of the net solubility of plutonium in oxic natural waters where Pu(V)O

G. R. Choppin; A. H. Bond; P. M. Hromadka

1997-01-01

116

Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions  

SciTech Connect

This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

2000-09-28

117

Nitrate Absorption by Barley  

PubMed Central

The influence of protein synthesis and nitrate reductase activity on nitrate absorption by barley (Hordeum vulgare L.) was investigated. Cycloheximide decreased nitrate absorption. Pretreatment studies showed that cycloheximide affects either energy transfer or nitrate reductase activity or both. Illumination increased plant capacity for nitrate absorption, possibly through increased energy supply and/or increased nitrate reductase activity. There was a positive correlation between nitrate reductase activity and light. Inhibiting the development of nitrate reductase activity by tungstate decreased nitrate absorption. At least two nitrate transport systems are thus proposed in barley: one operating in the dark, with little nitrate reductase activity detectable; and one closely correlated with nitrate reductase activity. Total absorption is the sum of dark absorption and absorption facilitated by nitrate reductase. PMID:16659426

Rao, K. Prasad; Rains, D. William

1976-01-01

118

Plutonium Finishing Plant (PFP) Final Safety Analysis Report (FSAR) [SEC 1 THRU 11  

SciTech Connect

The Plutonium Finishing Plant (PFP) is located on the US Department of Energy (DOE) Hanford Site in south central Washington State. The DOE Richland Operations (DOE-RL) Project Hanford Management Contract (PHMC) is with Fluor Hanford Inc. (FH). Westinghouse Safety Management Systems (WSMS) provides management support to the PFP facility. Since 1991, the mission of the PFP has changed from plutonium material processing to preparation for decontamination and decommissioning (D and D). The PFP is in transition between its previous mission and the proposed D and D mission. The objective of the transition is to place the facility into a stable state for long-term storage of plutonium materials before final disposition of the facility. Accordingly, this update of the Final Safety Analysis Report (FSAR) reflects the current status of the buildings, equipment, and operations during this transition. The primary product of the PFP was plutonium metal in the form of 2.2-kg, cylindrical ingots called buttoms. Plutonium nitrate was one of several chemical compounds containing plutonium that were produced as an intermediate processing product. Plutonium recovery was performed at the Plutonium Reclamation Facility (PRF) and plutonium conversion (from a nitrate form to a metal form) was performed at the Remote Mechanical C (RMC) Line as the primary processes. Plutonium oxide was also produced at the Remote Mechanical A (RMA) Line. Plutonium processed at the PFP contained both weapons-grade and fuels-grade plutonium materials. The capability existed to process both weapons-grade and fuels-grade material through the PRF and only weapons-grade material through the RMC Line although fuels-grade material was processed through the line before 1984. Amounts of these materials exist in storage throughout the facility in various residual forms left from previous years of operations.

ULLAH, M K

2001-02-26

119

Method for improved decomposition of metal nitrate solutions  

DOEpatents

A method for co-conversion of aqueous solutions of one or more heavy metal nitrates is described, wherein thermal decomposition within a temperature range of about 300 to 800/sup 0/C is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Haas, P.A.; Stines, W.B.

1981-01-21

120

Evaluation of nitrate and nitrite destruction/separation technologies  

SciTech Connect

This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

Hobbs, D.T.

1997-08-29

121

Method for improved decomposition of metal nitrate solutions  

DOEpatents

A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Haas, Paul A. (Knoxville, TN); Stines, William B. (Knoxville, TN)

1983-10-11

122

31. VIEW OF A WORKER HOLDING A PLUTONIUM 'BUTTON.' PLUTONIUM, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. VIEW OF A WORKER HOLDING A PLUTONIUM 'BUTTON.' PLUTONIUM, A MAN-MADE SUBSTANCE, WAS RARE. SCRAPS RESULTING FROM PRODUCTION AND PLUTONIUM RECOVERED FROM RETIRED NUCLEAR WEAPONS WERE REPROCESSED INTO VALUABLE PURE-PLUTONIUM METAL (9/19/73). - Rocky Flats Plant, Bounded by Indiana Street & Routes 93, 128 & 72, Golden, Jefferson County, CO

123

Photochemical reduction of uranyl nitrate  

SciTech Connect

The photochemical reduction of uranyl nitrate solutions to tetravalent uranium was investigated as a means of producing uranium dioxide feed for the saltless direct oxide reduction (SDOR) process. At high uranium concentrations, reoxidation of U{sup +4} occurs rapidly. The kinetics of the nitric oxidation of tetravalent uranium depend on the concentrations of hydrogen ion, nitrate ion, nitrous acid, and tetravalent uranium in the same manner as was reported elsewhere for the nitrate oxidation of PU{sup +3}. Reaction rate data were successfully correlated with a mechanism in which nitrogen dioxide is the reactive intermediate. Addition of a nitrous acid scavenger suppresses the reoxidation reaction. An immersion reactor employing a mercury vapor lamp gave reduction times fast enough for routine production usage. Precipitation techniques for conversion of aqueous U(NO{sub 3}){sub 4} to hydrous UO{sub 2} were evaluated. Prolonged dewatering times tended to make the process time consuming. Use of 3- to 4-M aqueous NaOH gave the best dewatering times observed. Reoxidation of the UO{sub 2} by water of hydration was encountered, which required the drying process to be carried out under a reducing atmosphere.

Duerksen, W.K.

1993-10-20

124

The acid catalyzed nitration of methanol: formation of methyl nitrate via aerosol chemistry  

Microsoft Academic Search

The aqueous phase acid-catalyzed reaction of methanol (CH3OH) with nitric acid (HNO3) to yield methyl nitrate (CH3ONO2) under atmospheric conditions has been investigated using gas-phase infrared spectroscopy. Reactions were conducted in aqueous\\u000a sulfuric acid solutions (50.5–63.6 wt.%) with [CH3OH]?=?0.00005–0.005 M and [HNO3]?=?0.02–0.21 M, at 278.2–328.6 K. Methyl nitrate production rates increased linearly with CH3OH and HNO3 concentrations and exponentially with sulfuric acid weight percent

Laura T. Iraci; Brent G. Riffel; Carly B. Robinson; Rebecca R. Michelsen; Rachel M. Stephenson

2007-01-01

125

Plutonium radiation surrogate  

DOEpatents

A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

Frank, Michael I. (Dublin, CA)

2010-02-02

126

Ultra-small plutonium oxide nanocrystals: an innovative material in plutonium science.  

PubMed

Apart from its technological importance, plutonium (Pu) is also one of the most intriguing elements because of its non-conventional physical properties and fascinating chemistry. Those fundamental aspects are particularly interesting when dealing with the challenging study of plutonium-based nanomaterials. Here we show that ultra-small (3.2±0.9?nm) and highly crystalline plutonium oxide (PuO2 ) nanocrystals (NCs) can be synthesized by the thermal decomposition of plutonyl nitrate ([PuO2 (NO3 )2 ]?3?H2 O) in a highly coordinating organic medium. This is the first example reporting on the preparation of significant quantities (several tens of milligrams) of PuO2 NCs, in a controllable and reproducible manner. The structure and magnetic properties of PuO2 NCs have been characterized by a wide variety of techniques (powder X-ray diffraction (PXRD), X-ray absorption fine structure (XAFS), X-ray absorption near edge structure (XANES), TEM, IR, Raman, UV/Vis spectroscopies, and superconducting quantum interference device (SQUID) magnetometry). The current PuO2 NCs constitute an innovative material for the study of challenging problems as diverse as the transport behavior of plutonium in the environment or size and shape effects on the physics of transuranium elements. PMID:25042621

Hudry, Damien; Apostolidis, Christos; Walter, Olaf; Janssen, Arne; Manara, Dario; Griveau, Jean-Christophe; Colineau, Eric; Vitova, Tonya; Prüssmann, Tim; Wang, Di; Kübel, Christian; Meyer, Daniel

2014-08-11

127

Low-level detection and quantification of Plutonium(III, IV, V,and VI) using a liquid core waveguide  

SciTech Connect

Understanding the aqueous chemistry of plutonium, in particular in environmental conditions, is often complicated by plutonium's complex redox chemistry. Because plutonium possesses four oxidation states, all of which can coexist in solution, a reliable method for the identification of these oxidation states is needed. The identification of plutonium oxidation states at low levels in aqueous solution is often accomplished through an indirect determination using series of liquid-liquid extraction procedures using oxidation state specific reagents such as HDEHP and TTA. While these methods, coupled with radioactive counting techniques provide superior limits of detection they may influence the plutonium redox equilibrium, are time consuming, waste intensive and costly. Other analytical methods such as mass spectrometry and radioactive counting as stand alone methods provide excellent detection limits but lack the ability to discriminate between the oxidation states of the plutonium ions in solution.

Wilson, Richard E.; Hu, Yung-Jin; Nitsche, Heino

2003-06-28

128

Dry sample storage system for an analytical laboratory supporting plutonium processing  

SciTech Connect

The Special Isotope Separation (SIS) plant is designed to provide removal of undesirable isotopes in fuel grade plutonium by the atomic vapor laser isotope separation (AVLIS) process. The AVLIS process involves evaporation of plutonium metal, and passage of an intense beam of light from a laser through the plutonium vapor. The laser beam consists of several discrete wavelengths, tuned to the precise wavelength required to ionize the undesired isotopes. These ions are attracted to charged plates, leaving the bulk of the plutonium vapor enriched in the desired isotopes to be collected on a cold plate. Major portions of the process consist of pyrochemical processes, including direct reduction of the plutonium oxide feed material with calcium metal, and aqueous processes for purification of plutonium in residues. The analytical laboratory for the plant is called the Material and Process Control Laboratory (MPCL), and provides for the analysis of solid and liquid process samples.

Treibs, H.A.; Hartenstein, S.D.; Griebenow, B.L.; Wade, M.A.

1990-07-25

129

ABSORPTION SPECTRA OF URANYL NITRATE IN ORGANIC SOLVENTS  

Microsoft Academic Search

Optical densities of UOâ(NOâ)â in aqueous HCl(pH 1 to ; 2) saturated with NHâNOâ, 4% orthophosphoric acid and 10% HâSO\\/; sub 4\\/ were measured at various wave lengths in order to compare uranyl nitrate ; absorption spectra in organic solvents with its absorption spectra in aqueous ; solutions. (R.V.J.);

S. I. Sinyakova; N. S. Klassova

1959-01-01

130

Plutonium dissolution process  

DOEpatents

A two-step process for dissolving plutonium metal, which two steps can be carried out sequentially or simultaneously. Plutonium metal is exposed to a first mixture containing approximately 1.0M-1.67M sulfamic acid and 0.0025M-0.1M fluoride, the mixture having been heated to a temperature between 45.degree. C. and 70.degree. C. The mixture will dissolve a first portion of the plutonium metal but leave a portion of the plutonium in an oxide residue. Then, a mineral acid and additional fluoride are added to dissolve the residue. Alteratively, nitric acid in a concentration between approximately 0.05M and 0.067M is added to the first mixture to dissolve the residue as it is produced. Hydrogen released during the dissolution process is diluted with nitrogen.

Vest, Michael A. (Oak Park, IL); Fink, Samuel D. (Aiken, SC); Karraker, David G. (Aiken, SC); Moore, Edwin N. (Aiken, SC); Holcomb, H. Perry (North Augusta, SC)

1996-01-01

131

Disposition of separated plutonium  

Microsoft Academic Search

In the immediate term, plutonium, recovered from dismantled nuclear warheads and from civil reprocessing plants, will have to be stored securely, and under international safeguards if possible. In the intermediate term, the principal alternatives for disposition of this plutonium are: irradiation in mixed?oxide (MOX) fuel assemblies in commercial unmodified light?water reactors or in specially adapted light?water reactors capable of operating

Frans Berkhout; Anatoli Diakov; Harold Feiveson; Helen Hunt; Edwin Lyman; Marvin Miller; Frank von Hippel

1993-01-01

132

COGEMA Experience in Uranous Nitrate Preparation  

SciTech Connect

Separation and purification of plutonium by PUREX process is based on a sequence of extraction and back extraction which requires reducing plutonium Pu IV (extractable form) into Pu III (inextractable form) Different reducers can be used to reduce Pu IV into Pu III. Early plants such as that for Magnox fuel at Sellafield used ferrous sulfamate while UP 1 at Marcoule used uranous sulfamate. These reducers are efficient and easy to prepare but generates ferric and/or sulphate ions and so complicates management of the wastes from the plutonium purification cycle. Recent plants such as UP3 and UP2 800 at La Hague, THORP at Sellafield, and RRP at Rokkasho Mura (currently under tests) use uranous nitrate (U IV) stabilized by hydrazinium nitrate (N{sub 2}H{sub 5}NO{sub 3}) and hydroxyl ammonium nitrate (HAN). In the French plants, uranous nitrate is used in U-Pu separation and alpha barrier and HAN is used in Pu purification. Compared to sulfamate, U IV does not generate extraneous chemical species and uranyl nitrate (U VI) generated by reducing Pu IV follows the main uranium stream. More over uranous nitrate is prepared from reprocessed purified uranyl nitrate taken at the outlet of the reprocessing plant. Hydrazine and HAN offer the advantage to be salt-free reagents. Uranous nitrate can be generated either by electrolysis or by catalytic hydrogenation process. Electrolytic process has been implemented in early plant UP 1 at Marcoule (when changing reducer from uranous sulfamate to uranous nitrate) and was used again in UP2 plant at La Hague. However, the electrolytic process presented several disadvantages such as a low conversion rate and problems associated with the use of mercury. Electrolysis cells with no mercury were developed for the Eurochemic plant in Belgium and then implemented in the first Japanese reprocessing plant in Tokai-Mura. But finally, in 1975, the electrolytic process was abandoned in favor of the catalytic hydrogenation process developed at La Hague. The yield of the operation and its simplicity were the main reasons for this choice. Nowadays, our catalytic hydrogenation process is used in all the commercial reprocessing plants worldwide: THORP at Sellafield, UP3 and UP2 800 at La Hague, and RRP at Rokkasho-Mura. In this process, uranyl nitrate is reduced to uranous nitrate by hydrogen in presence of a platinum based catalyst. Most of the plants implement the reaction in the same kind of reactor: 'co-current, up-flow and fixed-bed reactor'. For UP2 800 at La Hague, started in 1994, a new kind of reactor allowing a higher capacity has been developed. In this reactor, the catalyst bed is not fixed but circulating (fluidized bed). The aim of the paper is to describe both reactor technology implemented in La Hague (fixed bed and fluidized bed), to show their performance in terms of capacity and yield and to compare their operating and maintenance principles. (authors)

Tison, E. [COGEMA, AREVA Group, Etablissement de La Hague, 50440 Beaumont La Hague Cedex (France); Bretault, Ph. [SGN, AREVA Group, 1 rue des Herons, 78182 St Quentin Yvelines Cedex (France)

2006-07-01

133

Alkali metal nitrate purification  

DOEpatents

A process is disclosed for removing contaminants from impure alkali metal nitrates containing them. The process comprises heating the impure alkali metal nitrates in solution form or molten form at a temperature and for a time sufficient to effect precipitation of solid impurities and separating the solid impurities from the resulting purified alkali metal nitrates. The resulting purified alkali metal nitrates in solution form may be heated to evaporate water therefrom to produce purified molten alkali metal nitrates suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of purified alkali metal nitrates.

Fiorucci, Louis C. (Hamden, CT); Morgan, Michael J. (Guilford, CT)

1986-02-04

134

INTERCOMPARISON OF PLUTONIUM-239 MEASUREMENTS  

EPA Science Inventory

In 1977 the U.S. Environmental Protection Agency distributed calibrated solutions of plutonium-239 to laboratories interested in participating in an intercomparison study of plutonium analysis. Participants were asked to perform a quantitative radioactivity analysis of the soluti...

135

Pyrochemical processing of plutonium. Technology review report  

SciTech Connect

Non-aqueous processes are now in routine use for direct conversion of plutonium oxide to metal, molten salt extraction of americium, and purification of impure metals by electrorefining. These processes are carried out at elevated temperatures in either refractory metal crucibles or magnesium-oxide ceramics in batch-mode operation. Direct oxide reduction is performed in units up to 700 gram PuO/sub 2/ batch size with molten calcium metal as the reductant and calcium chloride as the reaction flux. Americium metal is removed from plutonium metal by salt extraction with molten magnesium chloride. Electrorefining is used to isolate impurities from molten plutonium by molten salt ion transport in a controlled potential oxidation-reduction cell. Such cells can purify five or more kilograms of impure metal per 5-day electrorefining cycle. The product metal obtained is typically > 99.9% pure, starting from impure feeds. Metal scrap and crucible skulls are recovered by hydriding of the metallic residues and recovered either as impure metal or oxide feeds.

Coops, M.S.; Knighton, J.B.; Mullins, L.J.

1982-09-08

136

Lithium metal reduction of plutonium oxide to produce plutonium metal  

DOEpatents

A method is described for the chemical reduction of plutonium oxides to plutonium metal by the use of pure lithium metal. Lithium metal is used to reduce plutonium oxide to alpha plutonium metal (alpha-Pu). The lithium oxide by-product is reclaimed by sublimation and converted to the chloride salt, and after electrolysis, is removed as lithium metal. Zinc may be used as a solvent metal to improve thermodynamics of the reduction reaction at lower temperatures. Lithium metal reduction enables plutonium oxide reduction without the production of huge quantities of CaO--CaCl.sub.2 residues normally produced in conventional direct oxide reduction processes.

Coops, Melvin S. (Livermore, CA)

1992-01-01

137

Plutonium 239 Equivalency Calculations  

SciTech Connect

This document provides the basis for converting actual weapons grade plutonium mass to a plutonium equivalency (PuE) mass of Plutonium 239. The conversion can be accomplished by performing calculations utilizing either: (1) Isotopic conversions factors (CF{sub isotope}), or (2) 30-year-old weapons grade conversion factor (CF{sub 30 yr}) Both of these methods are provided in this document. Material mass and isotopic data are needed to calculate PuE using the isotopic conversion factors, which will provide the actual PuE value at the time of calculation. PuE is the summation of the isotopic masses times their associated isotopic conversion factors for plutonium 239. Isotopic conversion factors are calculated by a normalized equation, relative to Plutonium 239, of specific activity (SA) and cumulated dose inhalation affects based on 50-yr committed effective dose equivalent (CEDE). The isotopic conversion factors for converting weapons grade plutonium to PuE are provided in Table-1. The unit for specific activity (SA) is curies per gram (Ci/g) and the isotopic SA values come from reference [1]. The cumulated dose inhalation effect values in units of rem/Ci are based on 50-yr committed effective dose equivalent (CEDE). A person irradiated by gamma radiation outside the body will receive a dose only during the period of irradiation. However, following an intake by inhalation, some radionuclides persist in the body and irradiate the various tissues for many years. There are three groups CEDE data representing lengths of time of 0.5 (D), 50 (W) and 500 (Y) days, which are in reference [2]. The CEDE values in the (W) group demonstrates the highest dose equivalent value; therefore they are used for the calculation.

Wen, J

2011-05-31

138

Tracing nitrate in watersheds  

NASA Astrophysics Data System (ADS)

Plants need nitrogen to grow, and nitrate is a common fertilizer ingredient, but high levels of nitrate contamination in drinking water sources can cause health problems. It is generally known that nitrogen flows through watersheds from upslope areas down to streams, but the relationships between upslope soil solution or groundwater nitrate concentrations and stream water nitrate levels—and the ways in which land use changes may alter this relationship—are not fully understood.

Balcerak, Ernie

2013-05-01

139

Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana  

NASA Technical Reports Server (NTRS)

Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

Tischner, R.; Ward, M. R.; Huffaker, R. C.

1989-01-01

140

Plutonium microstructures. Part 1  

SciTech Connect

This report is the first of three parts in which Los Alamos and Lawrence Livermore National Laboratory metallographers exhibit a consolidated set of illustrations of inclusions that are seen in plutonium metal as a consequence of inherent and tramp impurities, alloy additions, and thermal or mechanical treatments. This part includes illustrations of nonmetallic and intermetallic inclusions characteristic of major impurity elements as an aid to identifying unknowns. It also describes historical aspects of the increased purity of laboratory plutonium samples, and it gives the composition of the etchant solutions and describes the etching procedure used in the preparation of each illustrated sample. 25 figures.

Cramer, E.M.; Bergin, J.B.

1981-09-01

141

Plutonium in Concentrated Solutions  

SciTech Connect

Complex, high ionic strength media are used throughout the plutonium cycle, from its processing and purification in nitric acid, to waste storage and processing in alkaline solutions of concentrated electrolytes, to geologic disposal in brines. Plutonium oxidation/reduction, stability, radiolysis, solution and solid phase chemistry have been studied in such systems. In some cases, predictive models for describing Pu chemistry under such non-ideal conditions have been developed, which are usually based on empirical databases describing specific ion interactions. In Chapter 11, Non-Ideal Systems, studies on the behavior of Pu in various complex media and available model descriptions are reviewed.

Clark, Sue B.; Delegard, Calvin H.

2002-08-01

142

Mechanisms of nitrate tolerance  

Microsoft Academic Search

There is now little dispute that clinical tolerance of organic nitrates occurs, particularly when these drugs are used by themselves to treat patients with stable angina pectoris and congestive heart failure. Classical hypotheses of nitrate tolerance suggest the phenomenon to result from vascular depletion of critical sulfhydryl groups, which are necessary to bring about vasorelaxation from nitrates. While this mechanism

Ho-Leung Fung; John Anthony Bauer

1994-01-01

143

PLUTONIUM LOADING CAPACITY OF REILLEX HPQ ANION EXCHANGE COLUMN - AFS-2 PLUTONIUM FLOWSHEET FOR MOX  

SciTech Connect

Radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the dependence of column loading performance on the feed composition in the H-Canyon dissolution process for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). These loading experiments show that a representative feed solution containing {approx}5 g Pu/L can be loaded onto Reillex{trademark} HPQ resin from solutions containing 8 M total nitrate and 0.1 M KF provided that the F is complexed with Al to an [Al]/[F] molar ratio range of 1.5-2.0. Lower concentrations of total nitrate and [Al]/[F] molar ratios may still have acceptable performance but were not tested in this study. Loading and washing Pu losses should be relatively low (<1%) for resin loading of up to 60 g Pu/L. Loading above 60 g Pu/L resin is possible, but Pu wash losses will increase such that 10-20% of the additional Pu fed may not be retained by the resin as the resin loading approaches 80 g Pu/L resin.

Kyser, E.; King, W.; O'Rourke, P.

2012-07-26

144

Aspects of plutonium(IV) hydrous polymer chemistry. [Plutonium (IV) hydrolysis products  

SciTech Connect

The polymerization of Pu(IV) hydrolysis products in aqueous nitric acid solutions containing uranyl nitrate has been examined as a function of pH, temperature, and concentration. Even in the absence of the uranyl solute, an induction period usually follows the polymer growth stage during which time formation of primary hydrolysis products occurs. Uranyl nitrate retards the polymerization rate by approximately 35% in spite of the counteracting influence of the nitrate ions associated with this solute; evidence is presented to demonstrate that the uranyl ion attaches through hydroxyl bridges to active sites in the polymer network and functions as a chain-terminating unit. The rate of polymer growth has been shown to be third order with respect to Pu(IV). 7 references, 4 figures, 2 tables.

Toth, L.M.; Friedman, H.A.; Osborne, M.M.

1983-01-01

145

METHOD FOR OBTAINING PLUTONIUM METAL AND ALLOYS OF PLUTONIUM FROM PLUTONIUM TRICHLORIDE  

Microsoft Academic Search

A process is given for both reducing plutonium trichloride to plutonium ; metal using cerium as the reductant and simultaneously alloying such plutonium ; metal with an excess of cerium or cerium and cobalt sufficient to yield the ; desired nuclear reactor fuel composition. The process is conducted at a ; temperature from about 550 to 775 deg C, at

J. G. Reavis; J. A. Leary; W. J. Maraman

1962-01-01

146

Extraction of Uranium, Neptunium and Plutonium from Caustic Media  

SciTech Connect

5 Fundamental research on uranium, neptunium and plutonium separation from alkaline media using solvent extraction is being conducted. Specific extractants for these actinides from alkaline media have been synthesized to investigate the feasibility of selective removal of these elements. Two families of extractants have been studied: terephthalamide and tetra(hydroxybenzyl)ethylene diamine derivatives. Fundamental studies were conducted to characterize their extraction behavior from a wide variety of aqueous conditions. The terephthalamide derivatives exhibit a significant extraction strength along with a discriminatory behavior among the actinides, plutonium being extracted the most strongly. Quantitative extraction of plutonium and moderate extraction of neptunium and uranium was achieved from a simple caustic solution. Interestingly, strontium is also quantitatively extracted by these derivatives. However, their stability to highly caustic solutions still needs to be imp roved. Tetra(hydroxybenzyl)ethylene diamine derivatives exhibit a very good stability to caustic conditions and are currently being studied.

Delmau, Laetitia H.; Bonnesen, Peter V.; Engle, Nancy L.; Raymond, Kenneth N.; Xu, Jade

2004-03-28

147

Hydride-catalyzed corrosion of plutonium by air: Initiation by plutonium monoxide monohydride  

SciTech Connect

Chemistry and kinetics of air reactions with plutonium monoxide monohydride (PuOH) and with mixtures of the oxide hydride and plutonium metal are defined by results of pressure-volume-temperature (PVT) measurements. Test with specimens prepared by total and partial corrosion of plutonium in 0.05 M sodium chloride solution show that reaction of residual water continues to generate H{sub 2} after liquid water is removed by evacuation. Rapid exposure of PuOH to air at room temperature does not produce a detectable reaction, but similar exposure of a partially corroded metal sample containing Pu and PuOH results in hydride (PuH{sub x})-catalyzed corrosion of the residual Pu. Kinetics of he first-order reaction resulting in formation of the PuH{sub x} catalyst and of the indiscriminate reaction of N{sub 2} and O{sub 2} with plutonium metal are defined. The rate of the catalyzed Pu+air reaction is independent of temperature (E{sub a} = 0), varies as the square of air pressure, and equals 0.78 {+-} 0.03 g Pu/cm{sup 2} min in air at one atmosphere. The absence of pyrophoric behavior for PuOH and differences in the reactivities of PuOH and PuOH + Pu mixtures are attributed to kinetic control by gaseous reaction products. Thermodynamic properties of the oxide hydride are estimated, particle size distributions of corrosion products are presented, and potential hazards associated with products formed by aqueous corrosion of plutonium are discussed.

Allen, T.H.; Haschke, J.M.

1998-06-01

148

Plutonium: An introduction  

SciTech Connect

This report is a summary of the history and properties of plutonium. It presents information on the atoms, comparing chemical and nuclear properties. It looks at the history of the atom, including its discovery and production methods. It summarizes the metallurgy and chemistry of the element. It also describes means of detecting and measuring the presence and quantity of the element.

Condit, R.H.

1993-10-01

149

Atomic spectrum of plutonium  

SciTech Connect

This report contains plutonium wavelengths, energy level classifications, and other spectroscopic data accumulated over the past twenty years at Laboratoire Aime Cotton (LAC) Argonne National Laboratory (ANL), and Lawrence Livermore National Laboratory (LLNL). The primary purpose was term analysis: deriving the energy levels in terms of quantum numbers and electron configurations, and evaluating the Slater-Condon and other parameters from the levels.

Blaise, J.; Fred, M.; Gutmacher, R.G.

1984-08-01

150

NITRATE CONVERSION OF HB-LINE REILLEXTM HPQ RESIN  

SciTech Connect

Reillex{trademark} HPQ ion exchange resin is used by HB Line to remove plutonium from aqueous streams. Reillex{trademark} HPQ resin currently available from Vertellus Specialties LLC is a chloride ionic form, which can cause stress corrosion cracking in stainless steels. Therefore, HB Line Engineering requested that Savannah River National Laboratory (SRNL) convert resin from chloride form to nitrate form in the Engineering Development Laboratory (EDL). To perform this task, SRNL treated two batches of resin in 2012. The first batch of resin from Reilly Industries Batch 80302MA was initially treated at SRNL in 2001 to remove chloride. This batch of resin, nominally 30 liters, has been stored wet in carboys since that time until being retreated in 2012. The second batch of resin from Batch 23408 consisted of 50 kg of new resin purchased from Vertellus Specialties in 2012. Both batches were treated in a column designed to convert resin using downflow of 1.0 M sodium nitrate solution through the resin bed followed by rinsing with deionized water. Both batches were analyzed for chloride concentration, before and after treatment, using Neutron Activation Analysis (NAA). The resin specification [Werling, 2003] states the total chlorine and chloride concentration shall be less than 250 ppm. The resin condition for measuring this concentration is not specified; however, in service the resin would always be fully wet. Measurements in SRNL showed that changing from oven dry resin to fully wet resin, with liquid in the particle interstices but no supernatant, increases the total weight by a factor of at least three. Therefore, concentration of chlorine or chloride expressed as parts per million (ppm) decreases by a factor of three. Therefore, SRNL recommends measuring chlorine concentration on an oven dry basis, then dividing by three to estimate chloride concentration in the fully wet condition. Chloride concentration in the first batch (No.80302MA) was nearly the same before the current treatment (759 ppm dry) and after treatment (745 ppm dry or {approx}248 ppm wet). Treatment of the second batch of resin (No.23408) was very successful. Chloride concentration decreased from 120,000 ppm dry to an average of 44 ppm dry or {approx}15ppm wet, which easily passes the 250 ppm wet criterion. Per guidance from HB Line Engineering, SRNL blended Batch 80302 resin with Batch P9059 resin which had been treated previously by ResinTech to remove chloride. The chloride concentrations for the two drums of Batch P9059 were 248 ppm dry ({approx}83 ppm wet) {+-}22.8% and 583 ppm dry ({approx}194 ppm wet) {+-} 11.8%. The blended resin was packaged in five gallon buckets.

Steimke, J.; Williams, M.; Steeper, T.; Leishear, R.

2012-05-29

151

Complexation of Plutonium (IV) With Sulfate At Variable Temperatures  

SciTech Connect

The complexation of plutonium(IV) with sulfate at variable temperatures has been investigated by solvent extraction method. A NaBrO{sub 3} solution was used as holding oxidant to maintain the plutonium(IV) oxidation state throughout the experiments. The distribution ratio of Pu(IV) between the organic and aqueous phases was found to decrease as the concentrations of sulfate were increased. Stability constants of the 1:1 and 1:2 Pu(IV)-HSO{sub 4}{sup -} complexes, dominant in the aqueous phase, were calculated from the effect of [HSO{sub 4}{sup -}] on the distribution ratio. The enthalpy and entropy of complexation were calculated from the stability constants at different temperatures using the Van't Hoff equation.

Y. Xia; J.I. Friese; D.A> Moore; P.P. Bachelor; L. Rao

2006-10-05

152

Molecular Characterization of Actinide Oxocations from Protactinium to Plutonium  

SciTech Connect

This presentation addresses the structural characterization by EXAFS of actinide cations at oxidation states (V) and (VI) as one walks across the periodic table from Z = 91 (protactinium) to Z = 94 (plutonium). A structural comparison between Pa, U, Np and Pu oxocations in aqueous solution at formal oxidation states (V) and (VI) is carried out. These results are corroborated by quantum chemical and molecular dynamics calculations.

Den Auwer, C.; Guilbaud, P.; Guillaumont, D.; Moisy, P. [CEA Marcoule, DEN/DRCP/SCPS, 30207 Bagnols sur Ceze Cedex (France); Digandomenico, V.; Le Naour, C.; Trubert, D.; Simoni, E. [IPN Orsay, 91405 Orsay Cedex (France); Hennig, C.; Scheinost, A. [Forshungszentrum Rossendorf, Institute of Radiochemistry, P.O. Box 510119, D-01314 Dresden (Germany); Rossendorf Beamline at the European Synchrotron Radiation Facility, F-38043 Grenoble (France); Conradson, S. D. [LANL, Los Alamos, NM87545, NM (United States)

2007-02-02

153

Plutonium Finishing Plant. Interim plutonium stabilization engineering study  

SciTech Connect

This report provides the results of an engineering study that evaluated the available technologies for stabilizing the plutonium stored at the Plutonium Finishing Plant located at the hanford Site in southeastern Washington. Further processing of the plutonium may be required to prepare the plutonium for interim (<50 years) storage. Specifically this document provides the current plutonium inventory and characterization, the initial screening process, and the process descriptions and flowsheets of the technologies that passed the initial screening. The conclusions and recommendations also are provided. The information contained in this report will be used to assist in the preparation of the environmental impact statement and to help decision makers determine which is the preferred technology to process the plutonium for interim storage.

Sevigny, G.J.; Gallucci, R.H.; Garrett, S.M.K.; Geeting, J.G.H.; Goheen, R.S.; Molton, P.M.; Templeton, K.J.; Villegas, A.J. [Pacific Northwest Lab., Richland, WA (United States); Nass, R. [Nuclear Fuel Services, Inc. (United States)

1995-08-01

154

Lithium ion aqueous cells  

NASA Astrophysics Data System (ADS)

Lithium ion aqueous cells were investigated using lithium intercalating compounds as anodes and cathodes. The aqueous electrolyte consisted of 4 to 5 molar solutions of either lithium perchlorate or lithium nitrate which contained lithium hydroxide in millimolar amounts to make the solutions slightly basic with a pH of about 8.5. Several electrode combinations were evaluated using lithium intercalating compounds such as lithium cobalt oxide and lithium manganese oxide as cathodes and lithium vanadium oxide, lithium manganese oxide, titanium disulfide, and molybdenum dioxide as the anodes. The cell employing manganese oxide as both the anode and cathode exhibited good charge-discharge characteristics with an open circuit potential of about one volt.

Plichta, Edward J.; Behl, Wishvender K.

1995-02-01

155

Plutonium age dating reloaded  

NASA Astrophysics Data System (ADS)

Although the age determination of plutonium is and has been a pillar of nuclear forensic investigations for many years, additional research in the field of plutonium age dating is still needed and leads to new insights as the present work shows: Plutonium is commonly dated with the help of the 241Pu/241Am chronometer using gamma spectrometry; in fewer cases the 240Pu/236U chronometer has been used. The age dating results of the 239Pu/235U chronometer and the 238Pu/234U chronometer are scarcely applied in addition to the 240Pu/236U chronometer, although their results can be obtained simultaneously from the same mass spectrometric experiments as the age dating result of latter. The reliability of the result can be tested when the results of different chronometers are compared. The 242Pu/238U chronometer is normally not evaluated at all due to its sensitivity to contamination with natural uranium. This apparent 'weakness' that renders the age dating results of the 242Pu/238U chronometer almost useless for nuclear forensic investigations, however turns out to be an advantage looked at from another perspective: the 242Pu/238U chronometer can be utilized as an indicator for uranium contamination of plutonium samples and even help to identify the nature of this contamination. To illustrate this the age dating results of all four Pu/U clocks mentioned above are discussed for one plutonium sample (NBS 946) that shows no signs of uranium contamination and for three additional plutonium samples. In case the 242Pu/238U chronometer results in an older 'age' than the other Pu/U chronometers, contamination with either a small amount of enriched or with natural or depleted uranium is for example possible. If the age dating result of the 239Pu/235U chronometer is also influenced the nature of the contamination can be identified; enriched uranium is in this latter case a likely cause for the missmatch of the age dating results of the Pu/U chronometers.

Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Mayer, Klaus; Prohaska, Thomas

2014-05-01

156

4. VIEW OF PLUTONIUM CANISTER ON CHAINVEYOR. SCRAP PLUTONIUM WAS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. VIEW OF PLUTONIUM CANISTER ON CHAINVEYOR. SCRAP PLUTONIUM WAS COLLECTED INTO CANS AT INDIVIDUAL WORKSTATIONS. THE CANS WERE TRANSFERRED VIA THE CHAIN CONVEYOR TO A WORKSTATION IN MODULE C WHERE THE MATERIAL WAS COMPRESSED INTO BRIQUETTES FOR LATER USE. (6/20/93) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

157

CSER 00-003 Criticality Safety Evaluation report for PFP Magnesium Hydroxide Precipitation Process for Plutonium Stabilization Glovebox 3  

SciTech Connect

This Criticality Safety Evaluation Report analyzes the stabilization of plutonium/uranium solutions in Glovebox 3 using the magnesium hydroxide precipitation process at PFP. The process covered are the receipt of diluted plutonium solutions into three precipitation tanks, the precipitation of plutonium from the solution, the filtering of the plutonium precipitate from the solution, the scraping of the precipitate from the filter into boats, and the initial drying of the precipitated slurry on a hot plate. A batch (up to 2.5 kg) is brought into the glovebox as plutonium nitrate, processed, and is then removed in boats for further processing. This CSER establishes limits for the magnesium hydroxide precipitation process in Glovebox 3 to maintain criticality safety while handling fissionable material.

LAN, J.S.

2000-07-13

158

Nitrated phenols in fog  

NASA Astrophysics Data System (ADS)

Five nitrated phenols and some of their possible photochemical precursors as phenol, cresol and nitrate were identified in fog water from northeastern Bavaria. The concentrations in a rural and an urban area are presented, and the relationships observed between several of the compounds are discussed in terms of gas phase formation mechanisms. The levels of the nitrated phenols (5-300 nmole? -1) and phenol (<10-1000 nmole? -1) in fog were higher than the concentrations reported for rain.

Richartz, Heike; Reischl, Arthur; Trautner, Frank; Hutzinger, Otto

159

Cylodextrin Polymer Nitrate  

NASA Technical Reports Server (NTRS)

The development of the use of cyclodextrin nitrates as possible components of insensitive, high-energy energetics is outlined over a time period of 12 years. Four different types of cyclodextrin polymers were synthesized, nitrated, and evaluated regarding their potential use for the military and aerospace community. The synthesis of these novel cyclodextrin polymers and different nitration techniques are shown and the potential of these new materials is discussed.

Kosowski, Bernard; Ruebner, Anja; Statton, Gary; Robitelle, Danielle; Meyers, Curtis

2000-01-01

160

Plutonium Air Shipments  

NSDL National Science Digital Library

The Nuclear Control Institute created a web site in response to a proposed standard for the shipment of radioactive materials. This site presents two world maps showing both sea and air routes that are planned or already in use for the shipment of plutonium. A series of papers by NCI-affiliated scientists and observers on the subject of radioactive materials shipments sets out the NCI position against such shipments.

161

Gamma radiation characteristics of plutonium dioxide fuel  

NASA Technical Reports Server (NTRS)

Investigation of plutonium dioxide as an isotopic fuel for Radioisotope Thermoelectric Generators yielded the isotopic composition of production-grade plutonium dioxide fuel, sources of gamma radiation produced by plutonium isotopes, and the gamma flux at the surface.

Gingo, P. J.

1969-01-01

162

Application of ICP-QMS for the determination of plutonium in environmental samples for safeguards purposes.  

PubMed

Aiming to determine the plutonium amount as well as its isotopic composition, in particular, in swipe samples for safeguards purposes, an analytical method was developed with a plutonium separation step based on extraction chromatography using 2 cm TEVA columns and detection with quadrupole ICP-MS applying an ultra-sonic nebulizer coupled with membrane desolvation system. The method was successfully applied to New Brunswick plutonium certified reference materials as well as to Lawrence Livermore National Laboratory round robin samples, based on the round robin samples provided by the Institute for Reference Materials and Measurements (Belgium), as part of the Regular European Interlaboratory Measurement Evaluation Programme (REIMEP), campaign 16 (isotopic abundances of plutonium in plutonium nitrate samples), with a total plutonium amount between 1 and 0.25 ng per sample. After the introduction of an additional separation step, it was also possible to carry out precise and accurate total plutonium, (240)Pu/(239)Pu, (241)Pu/(239)Pu and (242)Pu/(239)Pu atom ratios determination in sediment sample showing its applicability to environmental samples in general, reaching a detection limit equivalent to 5 mBq(239)Pu kg(-1). PMID:17543430

Godoy, Maria Luiza D P; Godoy, José Marcus; Roldão, Luiz Alfredo

2007-01-01

163

Manufacturing of Plutonium Tensile Specimens  

SciTech Connect

Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

Knapp, Cameron M [Los Alamos National Laboratory

2012-08-01

164

Proliferation aspects of plutonium recycling  

Microsoft Academic Search

Plutonium recycling offers benefits in an energy perspective of sustainable development, and, moreover it contributes to non-proliferation. Prior to recycling, reactor-grade plutonium from light-water reactors does not lend itself easily to the assembly of explosive nuclear devices; thereafter, practically not at all. Control systems for material security and non-proliferation should identify and adopt several categories of plutonium covering various isotopic

Bruno Pellaud

2002-01-01

165

Prolifération et recyclage du plutonium  

NASA Astrophysics Data System (ADS)

Plutonium recycling offers benefits in an energy perspective of sustainable development, and, moreover it contributes to non-proliferation. Prior to recycling, reactor-grade plutonium from light-water reactors does not lend itself easily to the assembly of explosive nuclear devices; thereafter, practically not at all. Control systems for material security and non-proliferation should identify and adopt several categories of plutonium covering various isotopic mixtures associated with different fuel types, in order to better reflect the risks and to better focus their controls. The author proposes the adoption of three categories of plutonium. To cite this article: B. Pellaud, C. R. Physique 3 (2002) 1067-1079.

Pellaud, Bruno

2002-10-01

166

THE DECOMPOSITION OF NITRIC ACID CO-EXTRACTED WITH URANYL NITRATE INTO TRIBUTYL PHOSPHATE  

Microsoft Academic Search

The decomposition of nitric acid co-extracted with uranyl nitrate-into ; tributyl phosphate-kerosene solutions is studied in terms of the initial ; concentrations of nitric acid and uranyl nitrate in the aqueous phase and over a ; period of two months in the presence of light. The results show that ; decomposition reaches approximnte equilibrium after one month, that the ;

T Sato

1960-01-01

167

Drinking Water Problems: Nitrates  

E-print Network

High levels of nitrates in drinking water can be harmful for very young infants and susceptible adults. This publication explains how people are exposed to nitrates, what health effects are caused by them in drinking water and how to remove them....

Dozier, Monty; Melton, Rebecca; Hare, Michael; Hopkins, Janie; Lesikar, Bruce J.

2008-03-28

168

Photochemical preparation of plutonium pentafluoride  

DOEpatents

The novel compound plutonium pentafluoride may be prepared by the photodissociation of gaseous plutonium hexafluoride. It is a white solid of low vapor pressure, which consists predominantly of a face-centered cubic structure with a.sub.o =4.2709.+-.0.0005 .ANG..

Rabideau, Sherman W. (Los Alamos, NM); Campbell, George M. (Los Alamos, NM)

1987-01-01

169

Huge Seebeck coefficients in non-aqueous electrolytes  

E-print Network

The Seeebeck coefficients of the non-aqueous electrolytes tetrabutylammonium nitrate, tetraoctylphosphonium bromide and tetradodecylammonium nitrate in 1-octanol, 1-dodecanol and ethylene-glycol are measured in a temperature range from T=30 to T=45 C. The Seebeck coefficient is generally of the order of a few hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here we report huge values of 7 mV/K at 0.1M concentration for tetrabutylammonium nitrate in 1-dodecanol. These striking results open the question of unexpectedly large kosmotrope or "structure making" effects of tetraalkylammonium ions on the structure of alcohols.

M. Bonetti; S. Nakamae; M. Roger; P. Guenoun

2011-02-11

170

Recent results on the solubility of uranium and plutonium in Savannah River Site waste supernate  

SciTech Connect

High-level waste (HLW) is stored at the Savannah River Site (SRS) in a highly alkaline condition to prevent corrosion of the carbon steel storage tanks. Major components in the liquid phase include nitrate, hydroxide, nitrite, aluminate, carbonate and sulfate. Minor components include chloride, fluoride, oxalate and phosphate. The low solubility of uranium and plutonium in the HLW becomes significant to nuclear safety analyses when the supernate is evaporated to solids to conserve waste storage space and then redissolved to process for permanent disposal. The study of uranium and plutonium solubility in synthetic waste tank solutions was initiated to define actinide behavior during waste removal operations.

Karraker, D.G.; Hobbs, D.T.

1994-03-01

171

Theoretical study of plutonium(IV) complexes formed within the PUREX process: a proposal of a plutonium surrogate in fire conditions.  

PubMed

We present a relativistic quantum chemical study to determine the best surrogate for plutonium(IV) to be used in experimental investigations of the behavior of plutonium-nitrate-TBP in fire conditions that might occur in the nuclear fuel refining process known as PUREX. In this study geometries and stabilities of Pu(NO3)6(2-) and Pu(NO3)4(TBP)2 complexes were compared to that of equivalent complexes of selected elements from the lanthanide and actinide series (Ce, Th, U) chosen on the basis of similar ionic radii and stability as tetravalent species. PBE and PBE0 DFT functionals have proven to be sufficient and affordable for qualitative studies, performing as good as the wave function based correlated method MP2. On the basis of our results, cerium(IV) appears to be a good surrogate for plutonium(IV). PMID:25290588

Šulka, Martin; Cantrel, Laurent; Vallet, Valérie

2014-10-30

172

Studies on the Reverse Osmosis Treatment of Uranyl Nitrate Solution  

Microsoft Academic Search

The aqueous effluent generated in uranium processing, particularly in the nuclear fuel fabrication step, contains mainly uranium nitrate. This requires treatment before discharge into the environment to meet stringent standards. This paper presents the performance of cellulose acetate membranes with regard to rejection of uranium under reverse osmotic conditions for feed concentrations up to 200 mg\\/L of uranium, which corresponds

S. Prabhakar; Saly T. Panicker; B. M. Misra; M. P. S. Ramani

1992-01-01

173

Halide Ion Enhancement of Nitrate Ion Photolysis  

NASA Astrophysics Data System (ADS)

Nitrate ion photochemistry is an important source of NOx in the polar regions. It is uncertain whether coexisting ions such as halides play a role in nitrate photochemistry. The effect of halides on NO3 photolysis was investigated using photolysis experiments in 230 L Teflon chambers that contain deliquesced aerosols of NaBr:NaNO3, KBr:KNO3 and ternary mixtures of NaCl:NaBr:NaNO3. Gas phase NO2 and gaseous halogen products were measured as a function of photolysis time using long path FTIR, NOx chemiluminescence and API-MS (atmospheric pressure ionization mass spectrometry). Experiments were conducted with NO3- held at a constant 0.5 M and with the amount of total halide concentration varying from 0.25 M to 4 M. Studies on NaBr:NaNO3 mixtures suggest that as the bromide ion to nitrate ion ratio increases, there is an enhancement in the rate of production of NO2 in the nitrate-bromide mixtures over that formed in the photolysis of NaNO3. Molecular dynamic (MD) simulations provide molecular level insight into the ions near the air-water interface in the aqueous halide-nitrate mixtures. These studies suggest that the presence of sodium halides at the air-water interface may encourage some nitrate ions to approach the top layers of water, allowing for more efficient escape of photoproducts than is seen in the absence of halides. Experiments on mixtures of KBr:KNO3 are being conducted to determine potential cation effects. In addition, ternary mixtures of NaCl:NaBr:NaNO3 are being examined to determine the effects of mixtures of halides on production of NO2 and gaseous halogen products. The implications of this photochemistry for tropospheric chemistry will be discussed.

Richards, N. K.; Wingen, L. M.; Callahan, K. M.; Tobias, D. J.; Finlayson-Pitts, B. J.

2009-12-01

174

Allelochemical stress produced by aqueous leachate of Nicotiana plumbaginifolia Viv  

Microsoft Academic Search

The effects of aqueous leachate of Nicotiana plumbaginifolia Viv. on germination, seedling growth, amylase activity, sugar and starch contents of germinated seeds of maize (Zea mays L. cv. Uttam) were examined. Effects of leachate on photosynthetic pigments, protein content, activities of nitrate reductase\\u000a and some antioxidants were also studied. Higher concentration of aqueous leachate of N. plumbaginifolia reduced the germination

Amit Singh; Deepmala Singh; N. B. Singh

2009-01-01

175

Improved recovery and purification of plutonium at Los Alamos using macroporous anion exchange resin  

SciTech Connect

For almost 30 years, Los Alamos National Laboratory has used anion exchange in nitric acid as the major aqueous process or the recovery and purification of plutonium. One of the few disadvantages of this system is the particularly slow rate at which the anionic nitrato complex of Pu(IV) equilibrates with the resin. The Nuclear Materials Process Technology Group at Los Alamos recently completed an ion exchange development program that focused on improving the slow sorption kinetics that limits this process. A comprehensive investigation of modern anion exchange resins identified porosity and bead size as the properties that most influence plutonium sorption kinetics. Our study found that small beads of macroporous resin produced a dramatic increase in plutonium process efficiency. The Rocky Flats Plant has already adopted this improved ion exchange technology, and it currently is being evaluated for use in other DOE plutonium-processing facilities.

Marsh, S.F.; Mann, M.J. (ed.)

1987-05-01

176

LANL Plutonium-Processing Facilities National Security  

E-print Network

TA-55 PF-4 LANL Plutonium-Processing Facilities National Security At the Los Alamos National Laboratory (LANL), virtually all plutonium operations occur within the Plutonium Facility at Tech- nical Area, and it is the only fully operational, full capability plutonium facility in the nation. Thus, TA-55 supports a wide

177

APPENDIX G Partition Coefficients For Plutonium  

E-print Network

APPENDIX G Partition Coefficients For Plutonium #12;Appendix G Partition Coefficients For Plutonium G.1.0 Background A number of studies have focussed on the adsorption behavior of plutonium that Kd values for plutonium typically range over 4 orders of magnitude (Thibault et al., 1990). Also

178

Plutonium oxide dissolution  

SciTech Connect

Several processing options for dissolving plutonium oxide (PuO{sub 2}) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO{sub 2} typically generated by burning plutonium metal and PuO{sub 2} produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO{sub 2} in canyon dissolvers. The options involve solid solution formation of PuO{sub 2} With uranium oxide (UO{sub 2}) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO{sub 2} with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO{sub 2} materials may warrant further study.

Gray, J.H.

1992-09-30

179

Plutonium oxide dissolution  

SciTech Connect

Several processing options for dissolving plutonium oxide (PuO[sub 2]) from high-fired materials have been studied. The scoping studies performed on these options were focused on PuO[sub 2] typically generated by burning plutonium metal and PuO[sub 2] produced during incineration of alpha contaminated waste. At least two processing options remain applicable for dissolving high-fired PuO[sub 2] in canyon dissolvers. The options involve solid solution formation of PuO[sub 2] With uranium oxide (UO[sub 2]) and alloying incinerator ash with aluminum. An oxidative dissolution process involving nitric acid solutions containing a strong oxidizing agent, such as cerium (IV), was neither proven nor rejected. This uncertainty was due to difficulty in regenerating cerium (IV) ions during dissolution. However, recent work on silver-catalyzed dissolution of PuO[sub 2] with persulfate has demonstrated that persulfate ions regenerate silver (II). Use of persulfate to regenerate cerium (IV) or bismuth (V) ions during dissolution of PuO[sub 2] materials may warrant further study.

Gray, J.H.

1992-09-30

180

Vitrified magnesia dissolution and its impact on plutonium residue processing  

SciTech Connect

Aqueous chloride operations at the Los Alamos Plutonium Facility cannot directly dispose of acidic waste solutions because of compatibility problems with existing disposal lines. Consequently, all hydrochloric acid must be neutralized and filtered prior to exiting the facility. From a waste minimization standpoint, the use of spent magnesia pyrochemical crucibles as the acid neutralization agent is attractive since this process would take a stream destined for transuranic waste and use it as a reagent in routine plutonium residue processing. Since Los Alamos National Laboratory has several years of experience using magnesium hydroxide as a neutralizing agent for waste acid from plutonium processing activities, the use of spent magnesia pyrochemical crucibles appeared to be an attractive extension of this activity. In order to be competitive with magnesium hydroxide, however, size reduction of crucible shards had to be performed effectively within the constraints of glovebox operations, and acid neutralization time using crucible shards had to be comparable to neutralization times observed when using reagent-grade magnesium hydroxide. The study utilized non-plutonium-contaminated crucibles for equipment evaluation and selection and used nonradioactive acid solutions for completing the neutralization experiments. This paper discusses experience in defining appropriate size reduction equipment and presents results from using the magnesia crucibles for hydrochloric acid neutralization, a logical precursor to introduction into glovebox enclosures.

Keith W. Fife; Jennifer L. Alwin; Coleman A. Smith; Michael D. Mayne; David A. Rockstraw

2000-03-01

181

Dissolution behavior of plutonium containing zirconia-magnesia ceramics  

NASA Astrophysics Data System (ADS)

This study explores the dissolution properties of zirconia-magnesia ceramics containing plutonium as the basis of an inert matrix nuclear fuel. The magnesium oxide phase remains pure MgO, while the zirconia incorporates a small amount of magnesium oxide along with all of the plutonium oxide and erbium oxide. The performance of the material under reactor and repository environments was examined. Reactor conditions are examined using a pressure vessel to expose the material to 300 °C water. To assess the performance of the material as a waste form it was submerged in 90 °C water for 1000 h. In both aqueous dissolution studies there was minimal release of less than 0.8 wt.% of plutonium from the material. To examine the potential for recycling, the dissolution behavior of the fuel matrix was examined in acidic solutions: pure nitric acid and a nitric acid-hydrofluoric acid-peroxide solution. Both acidic media exhibit potential for dissolving plutonium from the zirconia matrix. The experiments performed in this study are meant to lay a foundation for the chemical performance of zirconia-magnesia inert matrix fuel containing fissile material and burnable poison.

Holliday, Kiel; Hartmann, Thomas; Cerefice, Gary; Czerwinski, Ken

2012-03-01

182

Dissolution Behavior of Plutonium Containing Zirconia-Magnesia Ceramics  

SciTech Connect

This study explores the dissolution properties of zirconia-magnesia ceramics containing plutonium as the basis of an inert atrix nuclear fuel. The magnesium oxide phase remains pure MgO, while the zirconia incorporates a small amount of magnesium oxide along with all of the plutonium oxide and erbium oxide. The performance of the material under reactor and repository environments was examined. Reactor conditions are examined using a pressure vessel to expose the material to 300 degrees C water. To assess the performance of the material as a waste form it was submerged in 90 degrees C water for 1000 h. In both aqueous dissolution studies there was minimal release of less than 0.8 wt.% of plutonium from the material. To examine the potential for recycling, the dissolution behavior of the fuel matrix was examined in acidic solutions: pure nitric acid and a nitric acid-hydrofluoric acid-peroxide solution. Both acidic media exhibit potential for dissolving plutonium from the zirconia matrix. The experiments performed in this study are meant to lay a foundation for the chemical performance of zirconia-magnesia inert matrix fuel containing fissile material and burnable poison.

Kiel Holliday; Thomas Hartmann; Gary Cerefice; Ken Czerwinski

2012-03-01

183

Production of microspheres of thorium oxide, uranium oxide and plutonium oxide and their mixtures containing carbon  

Microsoft Academic Search

A process is desclosed for the production of microspheres of thorium oxide, uranium oxide or plutonium oxide and mixtures thereof, containing carbon. The microspheres are prepared by first forming an aqueous alkaline solution of a salt of said metals which will precipitate to a solid form in a concentrated alkaline medium together with an alkaline polymerizable organic monomer and carbon,

G. Bezzi; A. Facchini; G. Martignani; M. Pastore

1980-01-01

184

Probing phonons in plutonium  

SciTech Connect

Plutonium (Pu) is well known to have complex and unique physico-chemical properties. Notably, the pure metal exhibits six solid-state phase transformations with large volume expansions and contractions along the way to the liquid state: {alpha} {yields} {beta} {yields} {gamma} {yields} {delta} {yields} {delta}{prime} {yields} {var_epsilon} {yields} liquid. Unalloyed Pu melts at a relatively low temperature {approx}640 C to yield a higher density liquid than that of the solid from which it melts, (Figure 1). Detailed understanding of the properties of plutonium and plutonium-based alloys is critical for the safe handling, utilization, and long-term storage of these important, but highly toxic materials. However, both technical and and safety issues have made experimental observations extremely difficult. Phonon dispersion curves (PDCs) are key experimenta l data to the understanding of the basic properties of Pu materials such as: force constants, sound velocities, elastic constants, thermodynamics, phase stability, electron-phonon coupling, structural relaxation, etc. However, phonon dispersion curves (PDCs) in plutonium (Pu) and its alloys have defied measurement for the past few decades since the discovery of this element in 1941. This is due to a combination of the high thermal-neutron absorption cross section of plutonium and the inability to grow the large single crystals (with dimensions of a few millimeters) necessary for inelastic neutron scattering. Theoretical simulations of the Pu PDC continue to be hampered by the lack of suitable inter -atomic potentials. Thus, until recently the PDCs for Pu and its alloys have remained unknown experimentally and theoretically. The experimental limitations have recently been overcome by using a tightly focused undulator x-ray micro-beam scattered from single -grain domains in polycrystalline specimens. This experimental approach has been applied successfully to map the complete PDCs of an fcc d-Pu-Ga alloy using the high resolution inelastic x-ray scattering (HRIXS) capability on ID28. The complete PDCs for an fcc Pu-0.6 wt% Ga alloy are plotted in Figure 2, and represent the first full set of phonon dispersions ever determined for any Pu-bearing materials. The solid curves (red) are calculated using a standard Born-von Karman (B-vK) force constant model. An adequate fit to the experimental data is obtained if interactions up to the fourth-nearest neighbours are included. The dashed curves (blue) are recent dynamical mean field theory (DMFT) results by Dai et al. The elastic moduli calculated from the slopes of the experimental phonon dispersion curves near the {Lambda} point are: C{sub 11} = 35.3 {+-} 1.4 GPa, C{sub 12} = 25.5 {+-} 1.5 GPa and C{sub 44} = 30.53 {+-} 1.1 GPa. These values are in excellent agreement with those of the only other measurement on a similar alloy (1 wt % Ga) using ultrasonic techniques as well as with those recently calculated from a combined DMFT and linear response theory for pure {delta}-Pu. Several unusual features, including a large elastic anisotropy, a small shear elastic modulus C{prime}, a Kohn-like anomaly in the T{sub 1}[011] branch, and a pronounced softening of the [111] transverse modes are found. These features can be related to the phase transitions of plutonium and to strong coupling between the lattice structure and the 5f valence instabilities. The HRIXS results also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory (DMFT) calculations for {delta}-plutonium. The experimental-theoretical agreements shown in Figure 2 in terms of a low shear elastic modulus C{prime}, a Kohn-like anomaly in the T{sub 1}[011] branch, and a large softening of the T[111] modes give credence to the DMFT approach for the theoretical treatment of 5f electron systems of which {delta}-Pu is a classic example. However, quantitative differences remain. These are the position of the Kohn anomaly along the T{sub 1}[011] branch, the energy maximum of the T[111] mode s

Wong, Joe; Krisch, M.; Farber, D.; Occelli, F.; Schwartz, A.; Chiang, T.C.; Wall, M.; Boro, C.; Xu, Ruqing (UIUC); (LLNL); (ESRF); (LANL)

2010-11-16

185

Solubility of plutonium and waste evaporation  

SciTech Connect

Chemical processing of irradiated reactor elements at the Savannah River Site separates uranium, plutonium and fission products; fission products and process-added chemicals are mixed with an excess of NaOH and discharged as a basic slurry into large underground tanks for temporary storage. The slurry is composed of base-insoluble solids that settle to the bottom of the tank; the liquid supemate contains a mixture of base-soluble chemicals--nitrates, nitrites aluminate, sulfate, etc. To conserve space in the waste tanks, the supemate is concentrated by evaporation. As the evaporation proceeds, the solubilities of some components are exceeded, and these species crystallize from solution. Normally, these components are soluble in the hot solution discharged from the waste tank evaporator and do not crystallize until the solution cools. However, concern was aroused at West Valley over the possibility that plutonium would precipitate and accumulate in the evaporator, conceivably to the point that a nuclear accident was possible. There is also a concern at SRS from evaporation of sludge washes, which arise from washing the base-insoluble solids ({open_quote}sludge{close_quote}) with ca. 1M NaOH to reduce the Al and S0{sub 4}{sup {minus}2} content. The sludge washes of necessity extract a low level of Pu from the sludge and are evaporated to reduce their volume, presenting the possibility of precipitating Pu. Measurements of the solubility of Pu in synthetic solutions of similar composition to waste supernate and sludge washes are described in this report.

Karraker, D.G.

1993-10-22

186

Low temperature oxidation of plutonium  

SciTech Connect

The initial oxidation of gallium stabilized {delta}-plutonium metal at 193 K has been followed using x-ray photoelectron spectroscopy. On exposure to Langmuir quantities of oxygen, plutonium rapidly forms a trivalent oxide followed by a tetravalent plutonium oxide. The growth modes of both oxides have been determined. Warming the sample in vacuum, the tetravalent oxide reduces to the trivalent oxide. The kinetics of this reduction reaction have followed and the activation energy has been determined to be 38.8 kJ mol{sup -1}.

Nelson, Art J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Roussel, Paul [AWE, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom)

2013-05-15

187

Criticality Calculations Using the Isopiestic Density Law of Actinide Nitrates  

SciTech Connect

Up to now, criticality safety experts used density laws fitted on experimental data and applied them outside the measurement range. Depending on the case, such an approach could be wrong for nitrate solutions. Seven components are concerned: UO{sub 2}(NO{sub 3}){sub 2}, U(NO{sub 3}){sub 4}, Pu(NO{sub 3}){sub 4}, Pu(NO{sub 3}){sub 3}, Th(NO{sub 3}){sub 4}, Am(NO{sub 3}){sub 3}, and HNO{sub 3}. To obviate this problem, a new methodology based on the thermodynamic concept of mixtures of binary electrolytes solutions (one electrolyte + water) at constant water activity, a so-called 'isopiestic' solution, has been developed by the Institute de Radioprotection et de Surete Nucleaire (IRSN) to calculate the nitrate solutions density. This paper presents its qualification by using criticality experiments. The theory and the implementation are also given.Qualification results of the uranyl and plutonium nitrate solutions show that the new density law (also called the isopiestic law) is in good agreement with the benchmarks. Thus, no bias is put into evidence for the uranium solutions, and a small negative bias equal to 0.2% is found for the plutonium solutions.Moreover, the isopiestic law corrects the observed 1% overestimation of k{sub eff} due to the empirical IRSN Leroy and Jouan density law for uranium solutions and the observed 3.4% underestimation of k{sub eff} due to the ARH-600 density law for plutonium solutions.The isopiestic density law has been implemented in CIGALES V2.0, the graphical user interface of the French criticality safety package CRISTAL that calculates the atom densities of nuclides (and writes the input file for CRISTAL computations)

Leclaire, Nicolas P. [Institut de Radioprotection et de Surete Nucleaire (France); Anno, Jacques A. [Institut de Radioprotection et de Surete Nucleaire (France); Courtois, Gerard [Institut de Radioprotection et de Surete Nucleaire (France); Dannus, Pascal [Institut National des Sciences et Techniques Nucleaires (France); Poullot, Gilles [Institut de Radioprotection et de Surete Nucleaire (France); Rouyer, Veronique [Institut de Radioprotection et de Surete Nucleaire (France)

2003-12-15

188

The chemistry of tributyl phosphate at elevated temperatures in the Plutonium Finishing Plant Process Vessels  

SciTech Connect

Potentially violent chemical reactions of the tributyl phosphate solvent used by the Plutonium Finishing Plant at the Hanford Site were investigated. There is a small probability that a significant quantity of this solvent could be accidental transferred to heated process vessels and react there with nitric acid or plutonium nitrate also present in the solvent extraction process. The results of laboratory studies of the reactions show that exothermic oxidation of tributyl phosphate by either nitric acid or actinide nitrates is slow at temperatures expected in the heated vessels. Less than four percent of the tributyl phosphate will be oxidized in these vented vessels at temperatures between 125{degrees}C and 250{degrees}C because the oxidant will be lost from the vessels by vaporization or decomposition before the tributyl phosphate can be extensively oxidized. The net amounts of heat generated by oxidation with concentrated nitric acid and with thorium nitrate (a stand-in for plutonium nitrate) were determined to be about -150 and -220 joules per gram of tributyl phosphate initially present, respectively. This is not enough heat to cause violent reactions in the vessels. Pyrolysis of the tributyl phosphate occurred in these mixtures at temperatures of 110{degrees}C to 270{degrees}C and produced mainly 1-butene gas, water, and pyrophosphoric acid. Butene gas generation is slow at expected process vessel temperatures, but the rate is faster at higher temperatures. At 252{degrees}C the rate of butene gas generated was 0.33 g butene/min/g of tributyl phosphate present. The measured heat absorbed by the pyrolysis reaction was 228 J/g of tributyl phosphate initially present (or 14.5 kcal/mole of tributyl phosphate). Release of flammable butene gas into process areas where it could ignite appears to be the most serious safety consideration for the Plutonium Finishing Plant.

Barney, G.S.; Cooper, T.D.

1994-06-01

189

Actinide recovery using aqueous biphasic extraction: Initial developmental studies  

SciTech Connect

Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

1992-08-01

190

Microdistribution and long-term retention of 239Pu (NO3)4 in the respiratory tracts of an acutely exposed plutonium worker and experimental beagle dogs.  

PubMed

The long-term retention of inhaled soluble forms of plutonium raises concerns as to the potential health effects in persons working in nuclear energy or the nuclear weapons program. The distributions of long-term retained inhaled plutonium-nitrate [(239)Pu (NO(3))(4)] deposited in the lungs of an accidentally exposed nuclear worker (Human Case 0269) and in the lungs of experimentally exposed beagle dogs with varying initial lung depositions were determined via autoradiographs of selected histologic lung, lymph node, trachea, and nasal turbinate tissue sections. These studies showed that both the human and dogs had a nonuniform distribution of plutonium throughout the lung tissue. Fibrotic scar tissue effectively encapsulated a portion of the plutonium and prevented its clearance from the body or translocation to other tissues and diminished dose to organ parenchyma. Alpha radiation activity from deposited plutonium in Human Case 0269 was observed primarily along the subpleural regions while no alpha activity was seen in the tracheobronchial lymph nodes of this individual. However, relatively high activity levels in the tracheobronchial lymph nodes of the beagles indicated the lymphatic system was effective in clearing deposited plutonium from the lung tissues. In both the human case and beagle dogs, the appearance of retained plutonium within the respiratory tract was inconsistent with current biokinetic models of clearance for soluble forms of plutonium. Bound plutonium can have a marked effect on the dose to the lungs and subsequent radiation exposure has the potential to increase cancer risk. PMID:22962267

Nielsen, Christopher E; Wilson, Dulaney A; Brooks, Antone L; McCord, Stacey L; Dagle, Gerald E; James, Anthony C; Tolmachev, Sergei Y; Thrall, Brian D; Morgan, William F

2012-11-01

191

Microdistribution and Long-Term Retention of 239Pu (NO3)4 in the Respiratory Tracts of an Acutely Exposed Plutonium Worker and Experimental Beagle Dogs  

SciTech Connect

The long-term retention of inhaled soluble forms of plutonium raises concerns as to the potential health effects in persons working in nuclear energy or the nuclear weapons program. The distributions of long-term retained inhaled plutonium-nitrate [239Pu (NO3)4] deposited in the lungs of an accidentally exposed nuclear worker (Human Case 0269) and in the lungs of experimentally exposed beagle dogs with varying initial lung depositions were determined via autoradiographs of selected histological lung, lymph node, trachea, and nasal turbinate tissue sections. These studies showed that both the human and dogs had a non-uniform distribution of plutonium throughout the lung tissue. Fibrotic scar tissue effectively encapsulated a portion of the plutonium and prevented its clearance from the body or translocation to other tissues and diminished dose to organ parenchyma. Alpha radiation activity from deposited plutonium in Human Case 0269 was observed primarily along the sub-pleural regions while no alpha activity was seen in the tracheobronchial lymph nodes of this individual. However, relatively high activity levels in the tracheobronchial lymph nodes of the beagles indicated the lymphatic system was effective in clearing deposited plutonium from the lung tissues. In both the human case and beagle dogs, the appearance of retained plutonium within the respiratory tract was inconsistent with current biokinetic models of clearance for soluble forms of plutonium. Bound plutonium can have a marked effect on the dose to the lungs and subsequent radiation exposure has the potential increase in cancer risk.

Nielsen, Christopher E.; Wilson, Dulaney A.; Brooks, Antone L.; McCord, Stacey; Dagle, Gerald E.; James, Anthony C.; Tolmachev, Sergei Y.; Thrall, Brian D.; Morgan, William F.

2012-11-01

192

Influence of chemical form, feeding regimen, and animal species on the gastrointestinal absorption of plutonium  

SciTech Connect

We evaluated the effect of chemical form and feeding regimen on the gastrointestinal (GI) absorption of plutonium in adult mice at plutonium concentrations relevant to the establishment of drinking water standards. Mean fractional GI absorption values in fasted adult mice were: Pu(VI) bicarbonate, 15 x 10/sup -4/; Pu(IV) bicarbonate, 20 x 10/sup -4/; Pu(IV) nitrate (pH2), 17 x 10/sup -4/; Pu(IV) citrate, 24 x 10/sup -4/; and Pu(IV) polymer, 3 x 10/sup -4/. Values in fed adult mice were: Pu(VI) bicarbonate, 1.4 x 10/sup -4/; Pu(IV) polymer, 0.3 x 10/sup -4/. Pu(VI) is the oxidation state in chlorinated drinking waters and Pu(IV) is the oxidation state in many untreated natural waters. To assess the validity of extrapolating data from mice to humans, we also determined the GI absorption of Pu(VI) bicarbonate in adult baboons with a dual-isotope method that does not require animal sacrifice. Fractional GI absorption values obtained by this method were 23 +- 10 x 10/sup -4/ for fasted baboons (n=5) and 1.4 +- 0.9 x 10/sup -4/ for fed baboons (n=3). We have so far validated this method in one baboon and are currently completing validation in two additional animals. At low plutonium concentrations, plutonium oxidation state (Pu(VI) vs Pu(IV)) and administration medium (bicarbonate vs nitrate vs citrate) had little effect on the GI absorption of plutonium in mice. Formation of Pu(IV) polymers and animal feeding decreased the GI absorption of plutonium 5- to 10-fold. The GI absorption of Pu(VI) bicarbonate in both fed and fasted adult baboons appeared to be the same as in fed and fasted adult mice, respectively. 17 refs., 2 tabs.

Bhattacharyya, M.H.; Larsen, R.P.; Cohen, N.; Ralston, L.G.; Oldham, R.D.; Moretti, E.S.; Ayres, L.

1985-01-01

193

DEVELOPMENT OF GLASS AND CRYSTALLINE CERAMIC FORMS FOR DISPOSITION OF EXCESS PLUTONIUM  

SciTech Connect

In the aftermath of the Cold War, the United States Department of Energy (DOE) has identified up to 50 metric tons of excess plutonium that needs to be dispositioned. The bulk of the material is slated to be blended with uranium and fabricated into a Mixed Oxide (MOX) fuel for subsequent burning in commercial nuclear reactors. Excess plutonium-containing impurity materials making it unsuitable for fabrication into MOX fuel will need to be dispositioned via other means. Glass and crystalline ceramics have been developed and studied as candidate forms to immobilize these impure plutonium feeds. A titanate-based ceramic was identified as an excellent actinide material host. This composition was based on Synroc compositions previously developed for nuclear waste immobilization. These titanate ceramics were found to be able to accommodate extremely high quantities of fissile material and exhibit excellent aqueous durability. A lanthanide borosilicate (LaBS) glass was developed to accommodate high concentrations of plutonium and to be very tolerant of impurities yet still maintain good aqueous durability. Recent testing of alkali borosilicate compositions showed promise of using these compositions to disposition lower concentrations of plutonium using existing high level waste vitrification processes. The developed waste forms all appear to be suitable for Pu disposition. Depending on the actual types and concentrations of the Pu residue streams slated for disposition, each waste form offers unique advantages.

Marra, James; Cozzi, A; Crawford, C.; Herman, C.; Marra, John; Peeler, D.

2009-09-10

194

Proceedings of the Plutonium Futures ? The Science 2006 Conference  

SciTech Connect

Plutonium Futures--The Science 2006 provided opportunities to examine present knowledge of the chemical and physical properties of plutonium and other actinides in complex media and materials; to discuss the current and emerging science (chemistry, physics, materials science, nuclear science, and environmental effects) of plutonium and actinides relevant to enhancing global nuclear security; and to exchange ideas. This international conference also provided a forum for illustrating and enhancing capabilities and interests, and assessing issues in these areas. U.S. and international scientists, engineers, faculty, and students from universities, national laboratories, and DOE's nuclear complex were encouraged to participate and make technical contributions. The Conference ran from Sunday, July 9th through Thursday, July 13th. A popular aspect of the conference was the opening tutorial session on Sunday afternoon intended for students and scientists new to the area of plutonium research. The tutorial was well attended by novices and veterans alike, and featured such diverse topics as; plutonium metallurgy, plutonium in the environment, and international arms control and nonproliferation. Two plenary lectures began each morning and each afternoon session and highlighted the breakout sessions on coordination/organometallic chemistry, solid-state physics, environmental chemistry, materials science, separations and reprocessing, advanced fuels and waste forms, phase transformations, solution and gas-phase chemistry, compounds and complexes, electronic structure and physical properties, and more. Chemistry Highlights--Among the many chemistry highlights presented in this proceedings are the overview of concepts and philosophies on inert nuclear fuel matrices and concerns about the ever-increasing amounts of minor actinides and plutonium generated in the fuel cycle. The various ideas involve multiple reduction schemes for these materials, suggesting fuels for 'burning' or 'cradle-to-grave' accountability for various reactor types. Related work is presented on identification of the unique reaction mechanisms and identification of the intermediate products, including Pu(III), at the end of the PUREX process. In the important area of nuclear forensics, actual scenarios of nuclear materials confiscation and the successes of applying forensics protocols to determine attribution and possible intention are provided. In the area of reactor incidents, there is no other place on Earth like the Chernobyl Site Object Shelter and radioactive aerosol particle characterization studies reflect an important effort described herein. An additional report from another unique environmental site presents results on radionuclide monitoring, fate, and transport in the ecosystem of the Yenisei River in the Krasoyarsk region. In the area of nuclear waste disposal, a study of the ion irradiation damage to pyrochlore compounds with varying amounts of host elements and actinide dopants is presented. Papers on both the aqueous and nonaqueous chemistry of plutonium and other actinides are presented including anhydrous coordination chemistry and redox behavior in the presence of humic materials and the their sorption on common minerals in the environment. Also published herein are reports on the field of anhydrous coordination chemistry of the transuranic elements where there is scarce information. Solid-State and Materials Highlights--Plutonium solid-state and materials research is represented in these proceedings by a wealth of leading edge discovery class research. The breadth of this research is reflected in the topics covered: solid-state; materials science; superconductivity; phase changes, phonons, and entropy; electronic structure and physical properties; surface science and corrosion; and radiation effects, defects, impurities, and property changes. Indeed the scientific challenge and excitement of plutonium can best be highlighted by quoting the tutorial prospectus of Drs. Sarrao and Schwartz. 'Plutonium has long been recognized as a complex and scie

Fluss, M; Hobart, D; Allan, P; Jarvinen, G

2007-07-12

195

Nitrated phenols in the atmosphere: a review  

NASA Astrophysics Data System (ADS)

This paper reviews the data concerning the atmospheric occurrence of nitrophenols, both in the gas and in the condensed phase (rainwater, cloud, fog and snow). Data obtained from field campaigns are reported, together with a description of the analytical techniques employed for the identification and quantification of nitrophenols. Analysis is usually performed using techniques such as High Performance Liquid Chromatography (HPLC) or Gas Chromatography-Mass Spectrometry (GC-MS), with the sampling method largely determined according to the matrix under investigation. The sources of atmospheric nitrophenols include direct emissions resulting from combustion processes, hydrolysis of pesticides (e.g. parathion) and the secondary formation of nitrophenols in the atmosphere. Atmospheric nitration of phenol can take place both in the gas and liquid phases, but the relative importance of these processes is still under discussion. The gas-phase nitration involves reaction between phenol and rad OH+ rad NO 2 during the day or rad NO 3+ rad NO 2 during the night. Gas-phase nitration during the day yields only 2-nitrophenol (2-NP); while during the night it is thought that both 2-NP and 4-nitrophenol (4-NP) may be formed. Because of many gaps in the experimental evidence it is apparent that more research is required to indicate whether the 4-NP present in the environment can be accounted for by this nighttime process. Nitration in the condensed phase can be initiated by electrophilic nitration agents such as N 2O 5 and ClNO 2. Other liquid-phase processes can also take place, in the presence of rad NO 3, nitrate and nitrite, in the dark and under irradiation. Condensed-phase processes have been shown to yield 2- and 4-NP in similar amounts. It is also important to consider the atmospheric sinks of nitrophenols. The rate constant for the reaction between 2-NP and rad OH in the gas phase is rather low (9.0×10 -13 cm 3 molecule -1 s -1), while incomplete data are available for the reaction with rad NO 3. In addition, condensed-phase processes might also represent an important nitrophenol sink. Potential loss routes include the reaction with radicals such as rad OH and rad NO 3 in aqueous solution as well as the nitration to form the dinitrophenols.

Harrison, Mark A. J.; Barra, Silvia; Borghesi, Daniele; Vione, Davide; Arsene, Cecilia; Iulian Olariu, Romeo

196

Ethylene\\/ethane separation and concentration by hollow fiber facilitated transport membrane module with permeation of silver nitrate solution  

Microsoft Academic Search

Novel hollow fiber facilitated transport membrane modules were used for ethylene\\/ethane separation using an aqueous silver nitrate solution as a carrier solution. In this membrane system, a feed gas consisting of 80mol% C2H4 and 20mol% C2H6 and an aqueous 4M silver nitrate solution are supplied to the lumen side (high pressure side, feed side) of a hollow fiber ultrafiltration membrane

Masaaki Teramoto; Satoshi Shimizu; Hideto Matsuyama; Norifumi Matsumiya

2005-01-01

197

Electrochemical reduction of nitrate in the presence of an amide  

DOEpatents

The electrochemical reduction of nitrates in aqueous solutions thereof in the presence of amides to gaseous nitrogen (N.sub.2) is described. Generally, electrochemical reduction of NO.sub.3 proceeds stepwise, from NO.sub.3 to N.sub.2, and subsequently in several consecutive steps to ammonia (NH.sub.3) as a final product. Addition of at least one amide to the solution being electrolyzed suppresses ammonia generation, since suitable amides react with NO.sub.2 to generate N.sub.2. This permits nitrate reduction to gaseous nitrogen to proceed by electrolysis. Suitable amides include urea, sulfamic acid, formamide, and acetamide.

Dziewinski, Jacek J. (Los Alamos, NM); Marczak, Stanislaw (Los Alamos, NM)

2002-01-01

198

Conversion of Uranium Oxide into Nitrate with Nitrogen Dioxide  

NASA Astrophysics Data System (ADS)

In order to decrease the amount of aqueous liquid waste discharged from nuclear fuel reprocessing, the conversion of uranium dioxide into its nitrate using liquefied nitrogen dioxide was studied. Uranium dioxide powder was immersed in liquefied nitrogen dioxide at 313 K after a pretreatment by the oxidation of the uranium dioxide with nitrogen dioxide and air at 523 K. Seventy-nine % of the uranium dioxide, whose initial feed amount was 0.3 g, was converted into a water soluble compound. Based on an XRD analysis of the compound, uranyl nitrate trihydrate (UO2(NO3)2·3H2O) was confirmed.

Sawada, Kayo; Hirabayashi, Daisuke; Enokida, Youichi; Yamamoto, Ichiro

199

New uranyl nitrate complex with N-cyclohexyl-2-pyrrolidone: a promising candidate for nuclear fuel reprocessing  

Microsoft Academic Search

Bis(N-cyclohexyl-2-pyrrolidone) uranyl nitrate complex was prepared from uranyl nitrate and N-cyclohexyl-2-pyrrolidone (NCP) in 7 M aqueous nitric acid solution with a yield of 68%. The yellow UO2(NO3)2(NCP)2 complex was precipitated from this highly acidic media and was characterized by NMR, IR and UV-vis spectroscopies.

T. R Varga; M Sato; Zs Fazekas; M Harada; Y Ikeda; H Tomiyasu

2000-01-01

200

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2014 CFR

...Ammonium nitrate and ammonium nitrate fertilizers. 148.205 Section 148.205 ...Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to...of ammonium nitrate and the following fertilizers composed of uniform,...

2014-10-01

201

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

...Ammonium nitrate and ammonium nitrate fertilizers. 148.205 Section 148.205 ...Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to...of ammonium nitrate and the following fertilizers composed of uniform,...

2012-10-01

202

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

...Ammonium nitrate and ammonium nitrate fertilizers. 148.205 Section 148.205 ...Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to...of ammonium nitrate and the following fertilizers composed of uniform,...

2011-10-01

203

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.  

Code of Federal Regulations, 2013 CFR

...Ammonium nitrate and ammonium nitrate fertilizers. 148.205 Section 148.205 ...Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to...of ammonium nitrate and the following fertilizers composed of uniform,...

2013-10-01

204

Plutonium solution analyzer  

SciTech Connect

A fully automated analyzer has been developed for plutonium solutions. It was assembled from several commercially available modules, is based upon segmented flow analysis, and exhibits precision about an order of magnitude better than commercial units (0.5%-O.05% RSD). The system was designed to accept unmeasured, untreated liquid samples in the concentration range 40-240 g/L and produce a report with sample identification, sample concentrations, and an abundance of statistics. Optional hydraulics can accommodate samples in the concentration range 0.4-4.0 g/L. Operating at a typical rate of 30 to 40 samples per hour, it consumes only 0.074 mL of each sample and standard, and generates waste at the rate of about 1.5 mL per minute. No radioactive material passes through its multichannel peristaltic pump (which remains outside the glovebox, uncontaminated) but rather is handled by a 6-port, 2-position chromatography-type loop valve. An accompanying computer is programmed in QuickBASIC 4.5 to provide both instrument control and data reduction. The program is truly user-friendly and communication between operator and instrument is via computer screen displays and keyboard. Two important issues which have been addressed are waste minimization and operator safety (the analyzer can run in the absence of an operator, once its autosampler has been loaded).

Burns, D.A.

1994-09-01

205

Plutonium focus area  

SciTech Connect

To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this new approach, EM developed a management structure and principles that led to the creation of specific Focus Areas. These organizations were designed to focus the scientific and technical talent throughout DOE and the national scientific community on the major environmental restoration and waste management problems facing DOE. The Focus Area approach provides the framework for intersite cooperation and leveraging of resources on common problems. After the original establishment of five major Focus Areas within the Office of Technology Development (EM-50, now called the Office of Science and Technology), the Nuclear Materials Stabilization Task Group (EM-66) followed the structure already in place in EM-50 and chartered the Plutonium Focus Area (PFA). The following information outlines the scope and mission of the EM, EM-60, and EM-66 organizations as related to the PFA organizational structure.

NONE

1996-08-01

206

Plutonium shipments - a supplement  

SciTech Connect

By means of a supplement to the stimulating analysis found in the comprehensive article by Professor Jon Van Dyke on `Sea Shipment of Japanese Plutonium under International Law`, published in Volume 24 of this journal, we feel that the following clarifications and additions are appropriate. Radioactive wastes are not covered by the 1989 Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal. Fir this reason, the Basel Conference adopted on March 22, 1989, along with the convention, Resolution 5 on Harmonization of Procedures of the Basel Convention and the Code of Practice for International Transactions Involving Nuclear Wastes. In accordance with Resolution 5, the provisions of the Basel Convention were taken into full account during the elaboration of the IAEA code, which ultimately was adopted by Resolution GC(XXXIV)/530 of the General Conference on Code of Practice on the International Transboundary Movement of Radioactive Waste (TMRW) of September 21, 1990. The IAEA code of practice and the respective regional instruments affirm, with respect to TMRW, the general principles of the Basel Convention, including the critical regime of prior notification and prior informed consent (PIC) that extend the scope of duties of notification, environmental impact assessment, and consultation with respect to transboundary interference as the duties have evolved under existing customary law.

Kwiatkowska, B.; Soons, A. [Netherlands Institute for the Law of the Sea, Utrecht (Netherlands)

1994-10-01

207

Nitrate uptake and nitrate reduction in synchronous Chlorella  

Microsoft Academic Search

Nitrate uptake was followed continuously in cultures of Chlorella sorokiniana using ionsensitive electrodes. During the lifecycle of the synchronous cell cultures, a drastic increase occurred in the first hour after the onset of the light. Nitrate uptake rate was shown to be dependent on illumination intensity, nitrate concentration, and temperature. These results point to an energy-linked uptake process. From the

Rudolf Tischner; Harald Lorenzen

1979-01-01

208

Tracking sources of unsaturated zone and groundwater nitrate contamination using nitrogen and oxygen stable isotopes at the Hanford site, Washington.  

PubMed

The nitrogen and oxygen isotopic compositions of nitrate in pore water extracts from unsaturated zone (UZ) core samples and groundwater samples indicate at least four potential sources of nitrate in groundwaters at the U.S. DOE Hanford Site in south-central Washington. Natural sources of nitrate identified include microbially produced nitrate from the soil column (delta15N of 4 - 8 per thousand, delta18O of -9 to 2 per thousand) and nitrate in buried caliche layers (delta15N of 0-8 per thousand, delta 18O of -6to 42 per thousand). Isotopically distinctindustrial sources of nitrate include nitric acid in low-level disposal waters (delta15N approximately per thousand, delta 18O approximately 23%o) per thousandnd co-contaminant nitrate in high-level radioactive waste from plutonium processing (6'5delta1of 8-33 % o, per thousand18delta oO -9 to 7%0). per thousandThe isotopic compositions of nitrate from 97 groundwater wells with concentrations up to 1290 mg/L NO3- have been analyzed. Stable isotope analyses from this study site, which has natural and industrial nitrate sources, provide a tool to distinguish nitrate sources in an unconfined aquiferwhere concentrations alone do not. These data indicate that the most common sources of high nitrate concentrations in groundwater at Hanford are nitric acid and natural nitrate flushed out of the UZ during disposal of low-level wastewater. Nitrate associated with high-level radioactive UZ contamination does not appear to be a major source of groundwater nitrate at this time. PMID:15952359

Singleton, Michael J; Woods, Katharine N; Conrad, Mark E; Depaolo, Donald J; Dresel, P Evan

2005-05-15

209

Preconceptual design for separation of plutonium and gallium by ion exchange  

SciTech Connect

The disposition of plutonium from decommissioned nuclear weapons, by incorporation into commercial UO{sub 2}-based nuclear reactor fuel, is a viable means to reduce the potential for theft of excess plutonium. This fuel, which would be a combination of plutonium oxide and uranium oxide, is referred to as a mixed oxide (MOX). Following power generation in commercial reactors with this fuel, the remaining plutonium would become mixed with highly radioactive fission products in a spent fuel assembly. The radioactivity, complex chemical composition, and large size of this spent fuel assembly, would make theft difficult with elaborate chemical processing required for plutonium recovery. In fabricating the MOX fuel, it is important to maintain current commercial fuel purity specifications. While impurities from the weapons plutonium may or may not have a detrimental affect on the fuel fabrication or fuel/cladding performance, certifying the effect as insignificant could be more costly than purification. Two primary concerns have been raised with regard to the gallium impurity: (1) gallium vaporization during fuel sintering may adversely affect the MOX fuel fabrication process, and (2) gallium vaporization during reactor operation may adversely affect the fuel cladding performance. Consequently, processes for the separation of plutonium from gallium are currently being developed and/or designed. In particular, two separation processes are being considered: (1) a developmental, potentially lower cost and lower waste, thermal vaporization process following PuO{sub 2} powder preparation, and (2) an off-the-shelf, potentially higher cost and higher waste, aqueous-based ion exchange (IX) process. While it is planned to use the thermal vaporization process should its development prove successful, IX has been recommended as a backup process. This report presents a preconceptual design with material balances for separation of plutonium from gallium by IX.

DeMuth, S.F.

1997-09-30

210

Plutonium recycle in French PWR plants  

Microsoft Academic Search

A significant amount of plutonium from pressurized water reactor (PWR) spent fuel reprocessing will be available in France as soon as 1990. Due to the breeder program delay, this amount will be sufficient to permit plutonium recycle in a large number of French PWR plants. According to the French spent fuel reprocessing policy, plutonium recycling approaches two concerns: (1) economic

M. Rome; G. Francillon; M. le Bars

1987-01-01

211

Plutonium-the element of surprise  

E-print Network

Plutonium-the element of surprise G.R.ChoppinandB.E.Stout This year marked the soth annivrsary ol the original isolation o{ plutonium, making ita relativenewcomerto the PeriodicTable.Ovrthe past 50 years plutonium has become more familiar to tho generslpublic than manyothor,olderelem6nts

Short, Daniel

212

Plutonium removal limit for the disposition of plutonium-bearing materials  

SciTech Connect

Recent changes in world politics have resulted in the United States reducing its nuclear weapons and stopping plutonium production. Prior plutonium production, dismantling warheads, and decontamination and decommissioning some facilities have produced plutonium-bearing materials which must continue to be managed. As each lot of material is processed, the processor must decide whether to remove the plutonium before discarding the material or to discard it without plutonium removal. DOE has developed a new method of making this decision, called the Plutonium Removal Limit System (PRLS). The system is based on defining a plutonium concentration above which the cost of disposing of plutonium-bearing materials will be less if plutonium is recovered and below which the cost will be less if plutonium is discarded (following suitable waste treatment). This method minimizes the overall cost to DOE for disposing of the existing inventory of plutonium-bearing materials. The method was used to analyze the plutonium-discard limit for all categories of plutonium-bearing materials currently at each site. This analysis indicated the need to standardize the way sites make the remove-versus-discard decision. For this purpose, a set of departmental plutonium removal limits was developed. DOE expects to approve implementing this new method at all facilities handling plutonium-bearing material in FY 93.

White, W.C. [USDOE, Washington, DC (United States); Mowery, B. [Los Alamos National Lab., NM (United States); Felt, R. [Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID (United States); King, F.; Hurley, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States)

1992-12-31

213

Plutonium removal limit for the disposition of plutonium-bearing materials  

SciTech Connect

Recent changes in world politics have resulted in the United States reducing its nuclear weapons and stopping plutonium production. Prior plutonium production, dismantling warheads, and decontamination and decommissioning some facilities have produced plutonium-bearing materials which must continue to be managed. As each lot of material is processed, the processor must decide whether to remove the plutonium before discarding the material or to discard it without plutonium removal. DOE has developed a new method of making this decision, called the Plutonium Removal Limit System (PRLS). The system is based on defining a plutonium concentration above which the cost of disposing of plutonium-bearing materials will be less if plutonium is recovered and below which the cost will be less if plutonium is discarded (following suitable waste treatment). This method minimizes the overall cost to DOE for disposing of the existing inventory of plutonium-bearing materials. The method was used to analyze the plutonium-discard limit for all categories of plutonium-bearing materials currently at each site. This analysis indicated the need to standardize the way sites make the remove-versus-discard decision. For this purpose, a set of departmental plutonium removal limits was developed. DOE expects to approve implementing this new method at all facilities handling plutonium-bearing material in FY 93.

White, W.C. (USDOE, Washington, DC (United States)); Mowery, B. (Los Alamos National Lab., NM (United States)); Felt, R. (Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID (United States)); King, F.; Hurley, J.D. (Westinghouse Savannah River Co., Aiken, SC (United States))

1992-01-01

214

Structure and spectroscopy of hydrated neptunyl(VI) nitrate complexes.  

PubMed

Complexation between hexavalent neptunium and nitrate was studied in aqueous nitric acid solution using optical absorption, vibrational and X-ray absorption spectroscopies. Distributions of aqueous [NpO2](2+), [NpO2(NO3)](+) and [NpO2(NO3)2] species were obtained as a function of nitric acid concentration between 0 and 14 M. The crystal structure of [NpO2(NO3)2(H2O)2]·H2O was determined. PMID:24042456

Lindqvist-Reis, Patric; Apostolidis, Christos; Walter, Olaf; Marsac, Remi; Banik, Nidhu Lal; Skripkin, Mikhail Yu; Rothe, Jörg; Morgenstern, Alfred

2013-11-21

215

Nanocrystalline thoria powders via glycine-nitrate combustion  

NASA Astrophysics Data System (ADS)

Nanocrystalline thoria powders were prepared by the combustion technique using glycine as a fuel and nitrate as an oxidizer. The technique involves the exothermic decomposition of viscous liquid prepared by thermal dehydration of the aqueous solution containing thorium nitrate and glycine. Thoria powders of different crystallite sizes, surface areas and sinterabilities were prepared by starting with two different fuel-to-oxidant molar ratios. The exothermic decomposition of viscous liquid, at about 200°C, containing thorium nitrate-to-glycine in molar ratio 1:1.2 yielded the well-crystalline nano-sized ThO 2 powder. Thoria powders prepared by this technique were shown to have a higher surface area ( >50 m2/ g) and could be sintered to highly dense pellets (?93% th.d.) at relatively low sintering temperature of 1300°C for 3 h.

Purohit, R. D.; Saha, S.; Tyagi, A. K.

2001-01-01

216

Plutonium inventory characterization technical evaluation report  

SciTech Connect

This is a technical report on the data, gathered to date, under WHC- SD-CP-TP-086, Rev. 1, on the integrity of the food pack cans currently being used to store plutonium or plutonium compounds at the Plutonium Finishing Plant. Workplan PFP-96-VO-009, `Inspection of Special Nuclear Material Using X-ray`, was used to gather data on material and containment conditions using real time radiography. Some of those images are included herein. A matrix found in the `Plutonium Inventory Characterization Implementation Plan` was used to categorize different plutonium items based upon the type of material being stored and the life expectancy of the containers.

Wittman, G.R., Westinghouse Hanford

1996-07-10

217

Sulfide remediation by pulsed injection of nitrate into a low temperature Canadian heavy oil reservoir.  

PubMed

Sulfide formation by oil field sulfate-reducing bacteria (SRB) can be diminished by the injection of nitrate, stimulating the growth of nitrate-reducing bacteria (NRB). We monitored the field-wide injection of nitrate into a low temperature (approximately 30 degrees C) oil reservoir in western Canada by determining aqueous concentrations of sulfide, sulfate, nitrate, and nitrite, as well as the activities of NRB in water samples from 3 water plants, 2 injection wells, and 15 production wells over 2 years. The injection water had a low sulfate concentration (approximately 1 mM). Nitrate (2.4 mM, 150 ppm) was added at the water plants. Its subsequent distribution to the injection wells gave losses of 5-15% in the pipeline system, indicating that most was injected. Continuous nitrate injection lowered the total aqueous sulfide output of the production wells by 70% in the first five weeks, followed by recovery. Batchwise treatment of a limited section of the reservoir with high nitrate eliminated sulfide from one production well with nitrate breakthrough. Subsequent, field-wide treatment with week-long pulses of 14 mM nitrate gave breakthrough at an additional production well. However, this trend was reversed when injection with a constant dose of 2.4 mM (150 ppm) was resumed. The results are explained by assuming growth of SRB near the injection wellbore due to sulfate limitation. Injection of a constant nitrate dose inhibits these SRB initially. However, because of the constant, low temperature of the reservoir, SRB eventually grow back in a zone further removed from the injection wellbore. The resulting zonation (NRB closest to and SRB further away from the injection wellbore) can be broken by batch-wise increases in the concentration of injected nitrate, allowing it to re-enter the SRB-dominated zone. PMID:20000549

Voordouw, Gerrit; Grigoryan, Aleksandr A; Lambo, Adewale; Lin, Shiping; Park, Hyung Soo; Jack, Thomas R; Coombe, Dennis; Clay, Bill; Zhang, Frank; Ertmoed, Ryan; Miner, Kirk; Arensdorf, Joseph J

2009-12-15

218

Roentgenoluminescence of hexahydrate of uranyl nitrate in phosphoric acid solution  

NASA Astrophysics Data System (ADS)

The fluorescence (FL) and roentgenoluminescence (XRL) spectra of yellow aqueous solution of hexahydrate of uranyl nitrate phosphoric acid solution have been measured. The XRL spectrum was compared with the XRL of the green alkali alumino-phosphate glasses doped with uranium. It was shown that both the FL and XRL were due to uranyl groups. The radiative transitions are ascribed to3?1u ?1?{g/+}.

Ožvoldová, M.

1992-08-01

219

Extraction of Plutonium From Spiked INEEL Soil Samples Using the Ligand-Assisted Supercritical Fluid Extraction (LA-SFE) Technique  

SciTech Connect

In order to investigate the effectiveness of ligand-assisted supercritical fluid extraction for the removal of transuranic contaminations from soils an Idaho National Engineering and Environmental Laboratory (INEEL) silty-clay soil sample was obtained from near the Radioactive Waste Management Complex area and subjected to three different chemical preparations before being spiked with plutonium. The spiked INEEL soil samples were subjected to a sequential aqueous extraction procedure to determine radionuclide portioning in each sample. Results from those extractions demonstrate that plutonium consistently partitioned into the residual fraction across all three INEEL soil preparations whereas americium partitioned 73% into the iron/manganese fraction for soil preparation A, with the balance partitioning into the residual fraction. Plutonium and americium were extracted from the INEEL soil samples using a ligand-assisted supercritical fluid extraction technique. Initial supercritical fluid extraction runs produced plutonium extraction technique. Initial supercritical fluid extraction runs produced plutonium extraction efficiencies ranging from 14% to 19%. After a second round wherein the initial extraction parameters were changed, the plutonium extraction efficiencies increased to 60% and as high as 80% with the americium level in the post-extracted soil samples dropping near to the detection limits. The third round of experiments are currently underway. These results demonstrate that the ligand-assisted supercritical fluid extraction technique can effectively extract plutonium from the spiked INEEL soil preparations.

Fox, R.V.; Mincher, B.J. (INEEL); Holmes, R.G.G. (British Nuclear Fuels, Inc.)

1999-08-01

220

Plutonium immobilization form evaluation  

SciTech Connect

The 1994 National Academy of Sciences study and the 1997 assessment by DOE`s Office of Nonproliferation and National Security have emphasized the importance of the overall objectives of the Plutonium Disposition Program of beginning disposition rapidly. President Clinton and other leaders of the G-7 plus one (`Political Eight`) group of states, at the Moscow Nuclear Safety And Security Summit in April 1996, agreed on the objectives of accomplishing disposition of excess fissile material as soon as practicable. To meet these objectives, DOE has laid out an aggressive schedule in which large-scale immobilization operations would begin in 2005. Lawrence Livermore National Laboratory (LLNL), the lead laboratory for the development of Pu immobilization technologies for the Department of Energy`s Office of Fissile Materials Disposition (MD), was requested by MD to recommend the preferred immobilization form and technology for the disposition of excess weapons-usable Pu. In a series of three separate evaluations, the technologies for the candidate glass and ceramic forms were compared against criteria and metrics that reflect programmatic and technical objectives: (1) Evaluation of the R&D and engineering data for the two forms against the decision criteria/metrics by a technical evaluation panel comprising experts from within the immobilization program. (2) Integrated assessment by LLNL immobilization management of the candidate technologies with respect to the weighted criteria and other programmatic objectives, leading to a recommendation to DOE/MD on the preferred technology based on technical factors. (3) Assessment of the decision process, evaluation, and recommendation by a peer review panel of independent experts. Criteria used to assess the relative merits of the immobilization technologies were a subset of the criteria previously used by MD to choose among disposition options leading to the Programmatic Environmental Impact Statement and Record of Decision for the Storage and Disposition of Weapons-Usable Fissile Materials, January 1997. Criteria were: (1) resistance to Pu theft, diversion, and recovery by a terrorist organization or rogue nation; (2) resistance to recovery and reuse by host nation; (3) technical viability, including technical maturity, development risk, and acceptability for repository disposal; (4) environmental, safety, and health factors; (5) cost effectiveness; and (6) timeliness. On the basis of the technical evaluation and assessments, in September, 1997, LLNL recommended to DOE/MD that ceramic technologies be developed for deployment in the planned Pu immobilization plant.

Gray, L. W., LLNL

1998-02-13

221

Trace determination of nitrated polycyclic aromatic hydrocarbons using liquid chromatography with on-line electrochemical reduction and fluorescence detection  

Microsoft Academic Search

An efficient clean-up procedure coupled with a high performance liquid chromatography (HPLC) with on-line electrochemical (EC) reduction and fluorescence detection (FLD) was developed to quantify nitrated polycyclic aromatic hydrocarbons (NPAHs) in the airborne particulate. In this process, NPAHs were extracted ultrasonically followed by analysis by using a reversed phase column with an aqueous eluent containing 70% aqueous acetonitrile and sodium

Ching-Tang Kuo; Hong-Wen Chen; Shaw-Tao Lin

2003-01-01

222

The chemistry, waste form development, and properties of the Nitrate to Ammonia and Ceramic (NAC) process  

SciTech Connect

A process for the conversion of alkaline, aqueous nitrate wastes to ammonia gas at low temperature, based upon the use of the active metal reductant aluminum, has been developed at the Oak Ridge National Laboratory (ORNL). The process is also well suited for the removal of low-level waste (LLW) radioelements and hazardous metals which report to the solid, alumina-based by-product. ne chemistry of the interaction of aluminum powders with nitrate, and other waste stream metals is presented.

Mattus, A.J.; Lee, D.D.; Youngblood, E.L.; Walker, J.F. Jr.; Tiegs, T.N.

1994-06-01

223

Some History of Nitrates  

NASA Astrophysics Data System (ADS)

The history of saltpeter is an interesting combination of chemistry, world trade, technology, politics, and warfare. Originally it was obtained from the dirt floors of stables, sheep pens, pigeon houses, caverns, and even peasants' cottages; any place manure and refuse accumulated in soil under dry conditions. When these sources became inadequate to meet demand it was manufactured on saltpeter plantations, located in dry climates, where piles of dirt, limestone, and manure were allowed to stand for three to five years while soil microbes oxidized the nitrogen to nitrate—an example of early bioengineering. Extensive deposits of sodium nitrate were mined in the Atacama Desert in northern Chile from 1830 until the mid 1920s when the mines were displaced by the Haber Ostwald process.

Barnum, Dennis W.

2003-12-01

224

PLUTONIUM SOLUBILITY IN SIMULATED SAVANNAH RIVER SITE WASTE SOLUTIONS  

SciTech Connect

To address the accelerated disposition of the supernate and salt portions of Savannah River Site (SRS) high level waste (HLW), solubility experiments were performed to develop a predictive capability for plutonium (Pu) solubility. A statistically designed experiment was used to measure the solubility of Pu in simulated solutions with salt concentrations and temperatures which bounded those observed in SRS HLW solutions. Constituents of the simulated waste solutions included: hydroxide (OH{sup -}), aluminate (Al(OH){sub 4}{sup -}), sulfate (SO{sub 4}{sup 2-}), carbonate (CO{sub 3}{sup 2-}), nitrate (NO{sub 3}{sup -}), and nitrite (NO{sub 2}{sup -}) anions. Each anion was added to the waste solution in the sodium form. The solubilities were measured at 25 and 80 C. Five sets of samples were analyzed over a six month period and a partial sample set was analyzed after nominally fifteen months of equilibration. No discernable time dependence of the measured Pu concentrations was observed except for two salt solutions equilibrated at 80 C which contained OH{sup -} concentrations >5 mol/L. In these solutions, the Pu solubility increased with time. This observation was attributed to the air oxidation of a portion of the Pu from Pu(IV) to the more soluble Pu(V) or Pu(VI) valence states. A data driven approach was subsequently used to develop a modified response surface model for Pu solubility. Solubility data from this study and historical data from the literature were used to fit the model. The model predicted the Pu solubility of the solutions from this study within the 95% confidence interval for individual predictions and the analysis of variance indicated no statistically significant lack of fit. The Savannah River National Laboratory (SRNL) model was compared with predicted values from the Aqueous Electrolyte (AQ) model developed by OLI Systems, Inc. and a solubility prediction equation developed by Delegard and Gallagher for Hanford tank waste. The agreement between measured or values predicted by the SRNL model and values predicted by the OLI AG model was very poor. The much higher predicted concentrations by the OLI AQ model appears to be the result of the model predicting the predominate Pu oxidation state is Pu(V) which is reported as unstable below sodium hydroxide (NaOH) concentrations of 6 M. There was very good agreement between the predicted Pu concentrations using the SRNL model and the model developed by Delegard and Gallagher with the exception of solutions that had very high OH{sup -} (15 M) concentrations. The lower Pu solubilities in these solutions were attributed to the presence of NO{sub 3}{sup -} and NO{sub 2}{sup -} which limit the oxidation of Pu(IV) to Pu(V).

Rudisill, T.; Hobbs, D.; Edwards, T.

2010-09-27

225

PLUTONIUM FUEL-CASTING FACILITY  

Microsoft Academic Search

An induction-heated glove-box-enclosed casting facility was used at ; Hanford for the melting and casting of experimental plutonium-containing fuel ; alloys. The alloys are prepared in furnaces with removable clay-graphite ; crucibles, supported by rammed alumina containment shells. The furnaces, which ; have capacities of 25 and 50 pounds of aluminum, are tilted by rotary hydraulic ; actuators. Furnace power

L. G. Merker; C. H. Bloomster

1963-01-01

226

Plutonium from Chernobyl in Poland  

Microsoft Academic Search

Samples of coniferous forest litter collected in POland, of known ?-emitters activity, have been analysed for ? emitting plutonium isotopes. Specific as well as surface activities of the samples have been determined. Chernobyl and global fallout components have been distinguished for each sample. The observed maximum surface activity for Chernobyl fallout is above 25 Bq m?2 (for all ?-emitting Pu

Jerzy W. Mietelski

1995-01-01

227

Plutonium Recycle: The Fateful Step  

ERIC Educational Resources Information Center

Calls attention to the fact that if the Atomic Energy Commission proceeds with its plans to authorize the nuclear power industry to use plutonium as a fuel in commercial nuclear reactors around the country, this will result in a dramatic escalation in the risks posed by nuclear power. (PEB)

Speth, J. Gustave; And Others

1974-01-01

228

Plutonium waste incineration using pyrohydrolysis  

SciTech Connect

Waste generated by Savannah River Site (SRS) plutonium operations includes a contaminated organic waste stream. A conventional method for disposing of the organic waste stream and recovering the nuclear material is by incineration. When the organic material is burned, the plutonium remains in the incinerator ash. Plutonium recovery from incinerator ash is highly dependent on the maximum temperature to which the oxide is exposed. Recovery via acid leaching is reduced for a high fired ash (>800{degree}C), while plutonium oxides fired at lower decomposition temperatures (400--800{degrees}C) are more soluble at any given acid concentration. To determine the feasibility of using a lower temperature process, tests were conducted using an electrically heated, controlled-air incinerator. Nine nonradioactive, solid, waste materials were batch-fed and processed in a top-heated cylindrical furnace. Waste material processing was completed using a 19-liter batch over a nominal 8-hour cycle. A processing cycle consisted of 1 hour for heating, 4 hours for reacting, and 3 hours for chamber cooling. The water gas shift reaction was used to hydrolyze waste materials in an atmosphere of 336% steam and 4.4% oxygen. Throughput ranged from 0.14 to 0.27 kg/hr depending on the variability in the waste material composition and density.

Meyer, M.L.

1991-12-31

229

COMPARISON OF MUTAGENIC ACTIVITIES OF SEVERAL PEROXYACL NITRATES  

EPA Science Inventory

Salmonella typhimurium, strain TA100 was exposed to a series of peroxyacyl nitrates including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), peroxybutyryl nitrate (PBN), peroxybenzoyl nitrate (PBzN), and chloroperoxyacetyl nitrate (CPAN). as-phase concentrations for t...

230

COMPARISON OF MUTAGENIC ACTIVITIES OF SEVERAL PEROXYACYL NITRATES  

EPA Science Inventory

Salmonella typhimurium strain TA100 was exposed to a series of peroxyacyl nitrates including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate peroxybutyryl nitrate (PBN), peroxybenzoyl nitrate (PBzN), and chlororoxyacetyl nitrate (CPAN). as phase concentrations for the individ...

231

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2012-10-01

232

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2013 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2013-10-01

233

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2014 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2014-10-01

234

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

...nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 ...nitrates, and certain ammonium nitrate fertilizers. (a) Except as provided in...Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than 70%...

2011-10-01

235

A review of the corrosion and pyrophoricity behavior of uranium and plutonium  

SciTech Connect

This report presents a review of the corrosion and pyrophoricity behavior of uranium and plutonium. For each element, the reactions with oxygen, water vapor, and aqueous solutions are described in terms of reaction rates, products, and mechanisms. Their pyrophoric tendencies in terms of measured ignition temperatures are discussed, and the effects of the important variables specific area, gas composition, and prior storage rare stated. The implications of the observed behavior for current storage issues are considered.

Totemeier, T.C.

1995-06-01

236

Nitrate and Prussic Acid Poisoning  

E-print Network

fertilized can accumu- late toxic levels. Turning cattle into holding pens or corrals full of manure with carelessweeds or grasses can result in immediate poisoning. Nitrates do not accumulate when there is nor- mal rainfall or irrigation. Under those.... Nitrate accumulates and is stored in lower leaves and stems, ready for the plant to mobilize and use when rapid growth resumes. Nitrate levels can change from day to day and even from morning until evening. Small grains can accumulate toxic levels...

Stichler, Charles; Reagor, John C.

2001-09-05

237

Lithium-boron anodes in nitrate thermal battery cells  

Microsoft Academic Search

A thermally activated electrochemical cell utilizes a lithium-boron anode and a molten nitrate electrolyte selected from the group consisting of lithium nitrate, a mixture of lithium nitrate and sodium nitrate, a mixture of lithium nitrate and potassium nitrate, and a mixture of lithium nitrate and sodium nitrate with potassium nitrate, to provide improved cell electrical performance. The electrolyte is contained

G. E. McManis; A. N. Fletcher; M. H. Miles

1985-01-01

238

Thermal Decomposition of Nitrated Tributyl Phosphate  

SciTech Connect

Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ``red oil`` explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material.

Paddleford, D.F. [Westinghouse Savannah River Company, Aiken, SC (United States); Hou, Y.; Barefield, E.K.; Tedder, D.W.; Abdel-Khalik, S.I. [Georgia Institute of Technology, GA (United States)

1995-01-01

239

Influence of Iron Redox Transformations on Plutonium Sorption to Sediments  

SciTech Connect

Plutonium subsurface mobility is primarily controlled by its oxidation state, which in turn is loosely coupled to the oxidation state of iron in the system. Experiments were conducted to examine the effect of sediment iron mineral composition and oxidation state on plutonium sorption and oxidation state. A pH 6.3 vadose zone sediment containing iron oxides and iron-containing phyllosilicates was treated with various complexants (ammonium oxalate) and reductants (dithionite-citrate-bicarbonate) to selectively leach and/or reduce iron oxide and phyllosilicate phases. Mössbauer spectroscopy was used to identify initial iron mineral composition of the sediment and monitor dissolution and reduction of iron oxides. Sorption of Pu(V) was monitored over one week for each of six treated sediment fractions. Plutonium oxidation state speciation in the aqueous and solid phases was monitored using solvent extraction, coprecipitation, and XANES. Mössbauer spectroscopy showed that the sediment contained 25-30% hematite, 60-65% Al-goethite, and <10%Fe(III) in phyllosilicate; there was no detectable Fe(II). Upon reduction with a strong chemical reductant (dithionite-citrate buffer, DCB), much of the hematite and goethite disappeared and the Fe in the phyllosilicate reduced to Fe(II). The rate of sorption was found to correlate with the 1 fraction of Fe(II) remaining within each treated sediment phase. Pu(V) was the only oxidation state measured in the aqueous phase, irrespective of treatment, whereas Pu(IV) and much smaller amounts of Pu(V) and Pu(VI) were measured in the solid phase. Surface-mediated reduction of Pu(V) to Pu(IV) occurred in treated and untreated sediment samples; Pu(V) remained on untreated sediment surface for two days before reducing to Pu(IV). Similar to the sorption kinetics, the reduction rate was correlated with sediment Fe(II) concentration. The correlation between Fe(II) concentrations and Pu(V) reduction demonstrates the potential impact of changing iron mineralogy on plutonium subsurface transport through redox transition areas. These findings should influence the conceptual models of long-term stewardship of Pu contaminated sites that have fluctuating redox conditions, such as vadose zones or riparian zones.

Hixon, Amy E.; Hu, Yung-Jin; Kaplan, Daniel I.; Kukkadapu, Ravi K.; Nitsche, Heino; Qafoku, Odeta; Powell, Brian A.

2010-10-01

240

Multi-generational stewardship of plutonium  

SciTech Connect

The post-cold war era has greatly enhanced the interest in the long-term stewardship of plutonium. The management of excess plutonium from proposed nuclear weapons dismantlement has been the subject of numerous intellectual discussions during the past several years. In this context, issues relevant to long-term management of all plutonium as a valuable energy resource are also being examined. While there are differing views about the future role of plutonium in the economy, there is a recognition of the environmental and health related problems and proliferation potentials of weapons-grade plutonium. The long-term management of plutonium as an energy resource will require a new strategy to maintain stewardship for many generations to come.

Pillay, K.K.S. [Los Alamos National Lab., NM (United States). Nuclear Materials Technology Div.

1997-10-01

241

Removal of nitrogenous compounds from aqueous solution by ozonation and ion exchange  

Microsoft Academic Search

Experiments were conducted to investigate the ammonia, nitrite and nitrate removal from aqueous solution using ozonation and ion exchange. The operating variables of the combined ozonation and ion exchange processes include the pH, initial concentration of nitrogenous compounds and flow rate of aqueous solution. The effects of those variables on the removal efficiencies of the nitrogeneous compounds by ozonation, or

Sheng H. Lin; Chang L. Wu

1996-01-01

242

Plutonium Immobilization Can Loading Concepts  

SciTech Connect

The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item.

Kriikku, E. [Westinghouse Savannah River Company, AIKEN, SC (United States); Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

1998-05-01

243

Alpha-plutonium's Grüneisen parameter  

NASA Astrophysics Data System (ADS)

Reported Grüneisen parameters ? of alpha-plutonium range from 3.0 to 9.6, which is remarkable because typical Grüneisen parameter uncertainty seldom exceeds ± 0.5. Our six new estimates obtained by different methods range from 3.2 to 9.6. The new estimates arise from Grüneisen's rule, from Einstein model and Debye model fits to low-temperature ?V/V, from the bulk modulus temperature dependence, from the zero-point-energy contribution to the bulk modulus, and from another Grüneisen relationship whereby ? is estimated from only the bulk modulus and volume changes with temperature (or pressure). We disregard several high estimates because of the itinerant-localized 5f-electron changes during temperature changes and pressure changes. Considering all these estimates, for alpha-plutonium, we recommend ? = 3.7 ± 0.4, slightly high compared with values for all elemental metals.

Ledbetter, Hassel; Lawson, Andrew; Migliori, Albert

2010-04-01

244

Alpha-plutonium's Grüneisen parameter.  

PubMed

Reported Grüneisen parameters ? of alpha-plutonium range from 3.0 to 9.6, which is remarkable because typical Grüneisen parameter uncertainty seldom exceeds ± 0.5. Our six new estimates obtained by different methods range from 3.2 to 9.6. The new estimates arise from Grüneisen's rule, from Einstein model and Debye model fits to low-temperature ?V/V, from the bulk modulus temperature dependence, from the zero-point-energy contribution to the bulk modulus, and from another Grüneisen relationship whereby ? is estimated from only the bulk modulus and volume changes with temperature (or pressure). We disregard several high estimates because of the itinerant-localized 5f-electron changes during temperature changes and pressure changes. Considering all these estimates, for alpha-plutonium, we recommend ? = 3.7 ± 0.4, slightly high compared with values for all elemental metals. PMID:21386421

Ledbetter, Hassel; Lawson, Andrew; Migliori, Albert

2010-04-28

245

Air transport of plutonium metal: content expansion initiative for the plutonium air transportable (PAT01) packaging  

SciTech Connect

The National Nuclear Security Administration (NNSA) has submitted an application to the Nuclear Regulatory Commission (NRC) for the air shipment of plutonium metal within the Plutonium Air Transportable (PAT-1) packaging. The PAT-1 packaging is currently authorized for the air transport of plutonium oxide in solid form only. The INMM presentation will provide a limited overview of the scope of the plutonium metal initiative and provide a status of the NNSA application to the NRC.

Caviness, Michael L [Los Alamos National Laboratory; Mann, Paul T [NNSA/ALBUQUERQUE; Yoshimura, Richard H [SNL

2010-01-01

246

Air transport of plutonium metal : content expansion initiative for the Plutonium Air Transportable (PAT-1) packaging.  

SciTech Connect

The National Nuclear Security Administration (NNSA) has submitted an application to the Nuclear Regulatory Commission (NRC) for the air shipment of plutonium metal within the Plutonium Air Transportable (PAT-1) packaging. The PAT-1 packaging is currently authorized for the air transport of plutonium oxide in solid form only. The INMM presentation will provide a limited overview of the scope of the plutonium metal initiative and provide a status of the NNSA application to the NRC.

Mann, Paul T. (National Nuclear Security Administration); Caviness, Michael L. (Los Alamos National Laboratory); Yoshimura, Richard Hiroyuki

2010-06-01

247

10 CFR 71.63 - Special requirement for plutonium shipments.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Special requirement for plutonium shipments. 71.63 Section 71.63...Standards § 71.63 Special requirement for plutonium shipments. Shipments containing plutonium must be made with the contents in...

2011-01-01

248

10 CFR 71.63 - Special requirement for plutonium shipments.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Special requirement for plutonium shipments. 71.63 Section 71.63...Standards § 71.63 Special requirement for plutonium shipments. Shipments containing plutonium must be made with the contents in...

2012-01-01

249

10 CFR 71.63 - Special requirement for plutonium shipments.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Special requirement for plutonium shipments. 71.63 Section 71.63...Standards § 71.63 Special requirement for plutonium shipments. Shipments containing plutonium must be made with the contents in...

2013-01-01

250

10 CFR 71.63 - Special requirement for plutonium shipments.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Special requirement for plutonium shipments. 71.63 Section 71.63...Standards § 71.63 Special requirement for plutonium shipments. Shipments containing plutonium must be made with the contents in...

2014-01-01

251

10 CFR 71.63 - Special requirement for plutonium shipments.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Special requirement for plutonium shipments. 71.63 Section 71.63...Standards § 71.63 Special requirement for plutonium shipments. Shipments containing plutonium must be made with the contents in...

2010-01-01

252

Plutonium Proliferation: The Achilles Heel of Disarmament  

Microsoft Academic Search

Plutonium is a byproduct of nuclear fission, and it is produced at the rate of about 70 metric tons a year in the world's nuclear power reactors. Concerns about civilian plutonium ran high in the 1970s and prompted enactment of the Nuclear Non-Proliferation Act of 1978 to give the United States a veto over separating plutonium from U.S.-supplied uranium fuel.

Leventhal

2001-01-01

253

PLUTONIUM METAL: OXIDATION CONSIDERATIONS AND APPROACH  

SciTech Connect

Plutonium is arguably the most unique of all metals when considered in the combined context of metallurgical, chemical, and nuclear behavior. Much of the research in understanding behavior and characteristics of plutonium materials has its genesis in work associated with nuclear weapons systems. However, with the advent of applications in fuel materials, the focus in plutonium science has been more towards nuclear fuel applications, as well as long term storage and disposition. The focus of discussion included herein is related to preparing plutonium materials to meet goals consistent with non-proliferation. More specifically, the emphasis is on the treatment of legacy plutonium, in primarily metallic form, and safe handling, packaging, and transport to meet non-proliferation goals of safe/secure storage. Elevated temperature oxidation of plutonium metal is the treatment of choice, due to extensive experiential data related to the method, as the oxide form of plutonium is one of only a few compounds that is relatively simple to produce, and stable over a large temperature range. Despite the simplicity of the steps required to oxidize plutonium metal, it is important to understand the behavior of plutonium to ensure that oxidation is conducted in a safe and effective manner. It is important to understand the effect of changes in environmental variables on the oxidation characteristics of plutonium. The primary purpose of this report is to present a brief summary of information related to plutonium metal attributes, behavior, methods for conversion to oxide, and the ancillary considerations related to processing and facility safety. The information provided is based on data available in the public domain and from experience in oxidation of such materials at various facilities in the United States. The report is provided as a general reference for implementation of a simple and safe plutonium metal oxidation technique.

Estochen, E.

2013-03-20

254

PROPRITS MAGNTIQUES ET STRUCTURE LECTRONIQUE DU PLUTONIUM  

E-print Network

699 PROPRI�T�S MAGN�TIQUES ET STRUCTURE �LECTRONIQUE DU PLUTONIUM J.-M. FOURNIER Centre d obtenus sur la susceptibilité magnétique du plutonium-03B1. Nous proposons ensuite un schéma de structure de bande que nous utilisons pour expliquer les anomalies d'autres propriétés physiques du plutonium

Paris-Sud XI, Université de

255

Molecular Control of Nitrate Reductase and Other Enzymes Involved in Nitrate Assimilation  

Microsoft Academic Search

Nitrate acts as both a nutrient and a signal in plants. Nitrate induces gene expression of enzymes for its metabolism into amino acids but also has other effects on plant metabolism and development. Familiar nitrate-induced enzymes are nitrate and nitrite reductases, nitrate transporters, glutamine synthetase, glutamate synthase, ferredoxin and ferredoxin NADP+ reductase. Microarray analysis of nitrate-stimulated gene expression has identified

Wilbur H. Campbell

256

PLUTONIUM ALLOYS CONTAINING CONTROLLED AMOUNTS OF PLUTONIUM ALLOTROPES OBTAINED BY APPLICATION OF HIGH PRESSURES  

Microsoft Academic Search

A method is given for making stabilized plutonium alloys which are free ; of voids and cracks and have a controlled amount of plutonium allotropes. The ; steps include adding at least 4.5 at.% of hafnium, indium, or erbium to the ; melted plutonium metal, homogenizing the resulting alloy at a temperature of 450 ; deg C, cooling to room

R. O. Elliott; K. A. Jr. Gschneidner

1962-01-01

257

PLUTONIUM FUELS DEVELOPMENT, PLUTONIUM METALLURGY OPERATION QUARTERLY REPORT-JANUARY, FEBRUARY, MARCH 1958  

Microsoft Academic Search

The last two of four Zircaloy-clad capsules containing aluminum-; plutonium and aluminum-- silicon--plutonium were discharged from the MTR and are ; undergoing examination. These capsules withstood a fractional bunnout of ; plutonium atoms of 55 to 60% as determined by flux monitoring wires attached to ; the capsule holder. Additional capsules of these fuel alloys containing a higher ; concentration

Wick

1958-01-01

258

PLUTONIUM ALLOYS CONTAINING CONTROLLED AMOUNTS OF PLUTONIUM ALLOTROPES OBTAINED BY APPLICATION OF HIGH PRESSURES  

Microsoft Academic Search

A method of making stabilized plutonium alloys which are free of voids ; and cracks and have a controlled amount of plutonium allotropes is described. ; The steps include adding at least 4.5 at.% of hafnium, indium, or erbium to the ; melted plutonium metal, homogenizing the resulting alloy at a temperature of 450 ; deg C, cooling to room

R. O. Elliott; K. A. Jr. Gschneidner

1962-01-01

259

Thorium plutonium (TREX) fuel for weapons-grade plutonium disposition in pressurized water reactors  

Microsoft Academic Search

The goal of this study was to create a pressurized water reactor (PWR) reactor assembly (17 x 17) that would burn weapons-grade plutonium (WGP). Current designs of mixed-oxide (MOX) fuels combine WGP with uranium as the fuel. MOX fuel assemblies will destroy plutonium, but only 40 to 50% of the plutonium present in the fuel. This percentage is limited by

C. Comfort; C. Ferguson; S. Klima; D. E. Lilly; F. Rahnema

1996-01-01

260

The Vapor Pressure of Plutonium Halides  

Microsoft Academic Search

Vapor pressure measurements have been made with three halides of plutonium by a modification of the Knudsen effusion method. Measurements with solid plutonium trifluoride from 1200°K to 1440°K give the vapor pressure-temperature relation log10pmm=12.468–21,120\\/T. Measurements with liquid plutonium trifluoride from 1440°K to 1770°K give log10pmm=11.273–19,400\\/T. Measurements with solid plutonium trichloride from 850°K to 1007°K give log10pmm=12.726–15,910\\/T; with liquid trichloride from

T. E. Phipps; G. W. Sears; R. L. Seifert; O. C. Simpson

1950-01-01

261

Aqueous ferrofluids based on manganese and cobalt ferrites  

Microsoft Academic Search

Synthesis of two new aqueous ferrofluids is performed chemically according to Massart's procedure. Manganese and cobalt ferrite magnetic particles are precipitated and treated in order to obtain colloidal sols by creating a charge density on their surface. Such “ionic” ferrofluids can be prepared in an acidic (after a treatment by ferric nitrate) or in an alkaline medium at a concentration

Francisco Augusto Tourinho; Raymonde Franck; René Massart

1990-01-01

262

21 CFR 172.160 - Potassium nitrate.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

2011-04-01

263

76 FR 47238 - Ammonium Nitrate From Russia  

Federal Register 2010, 2011, 2012, 2013, 2014

...Second Review] Ammonium Nitrate From Russia Determination On the basis of the record...antidumping duty order on ammonium nitrate from Russia would be likely to lead to continuation...2011), entitled Ammonium Nitrate from Russia: Investigation No....

2011-08-04

264

76 FR 11273 - Ammonium Nitrate From Russia  

Federal Register 2010, 2011, 2012, 2013, 2014

...Second Review)] Ammonium Nitrate From Russia AGENCY: United States International Trade...investigation on ammonium nitrate from Russia...investigation on ammonium nitrate from Russia would be likely to lead to...

2011-03-01

265

21 CFR 172.160 - Potassium nitrate.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160...CONSUMPTION Food Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a curing...

2010-04-01

266

Nitrate Removal in NITREXTM Permeable Reactive Barriers  

E-print Network

Nitrate Removal in NITREXTM Permeable Reactive Barriers: Investigating Denitrification Using a 15 (particularly of nitrate) to aquatic systems is a growing problem. The NITREXTM Permeable Reactive Barrier (PRB removal processes is at work. KEYWORDS: nitrate removal, denitrification, permeable reactive barrier

Vallino, Joseph J.

267

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

E-print Network

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.

American Society for Testing and Materials. Philadelphia

1994-01-01

268

Nitrates in congestive heart failure  

Microsoft Academic Search

Nitrates are commonly used in the therapy of congestive heart failure (CHF). They exert beneficial hemodynamic effects by decreasing left ventricular filling pressure and systemic vascular resistance while modestly improving cardiac output. The improvement in left ventricular function caused by nitrates is the result of combined reduction in outflow resistance and mitral regurgitation, while decreased pericardial constraint and subendocardial ischemia

Jocelyn Dupuis

1994-01-01

269

Development program to recycle and purify plutonium-238 oxide fuel from scrap  

SciTech Connect

Nuclear Materials Technology (NMT) Division has initiated a development program to recover and purify plutonium-238 oxide from impure sources. A glove box line has been designed and a process flowsheet developed to perform this task on a large scale. The initial effort has focused on purification of {sup 238}PuO{sub 2} fuel that fails to meet General Purpose Heat Source (GPHS) specifications because of impurities. The notable non-actinide impurities were silicon and phosphorus, but aluminum, chromium, iron and nickel were also near or in excess of limits specified by GPHS fuel powder specifications. Among actinide impurities, uranium is of paramount concern because {sup 234}U is the daughter of {sup 2238}Pu by alpha decay, and is the largest actinide impurity. An aqueous method based on nitric acid was selected for purification of the {sup 238}PuO{sub 2} fuel. All aqueous processing used high purity reagents, and was performed in PTFE apparatus to minimize introduction of new contaminants. Impure {sup 238}PuO{sub 2} was first dissolved in refluxing HNO{sub 3}/HF and then the solution was filtered. The dissolved {sup 238}Pu was adjusted to the trivalent state by an excess of reducing reagents to compensate for radiolytic effects, precipitated as plutonium(III) oxalate, and recovered by filtration. The plutonium(III) oxalate was subsequently calcined to convert the plutonium to the oxide. Decontamination factors for silicon, phosphorus and uranium were excellent. Decontamination factors for aluminum, chromium, iron and nickel were very good. The purity of the {sup 238}PuO{sub 2} recovered from this operation was significantly better than specifications. Efforts continue to develop the capability for efficient, safe, cost-effective, and environmentally acceptable methods to recover and purify {sup 238}PuO{sub 2} fuel in a glovebox environment. Plutonium-238 materials targeted for recovery includes impure oxide and scrap items that are lean in {sup 238}Pu values.

Schulte, L.D.; Silver, G.L.; Avens, L.R.; Jarvinen, G.D.; Espinoza, J.; Foltyn, E.M.; Rinehart, G.H.

1996-12-31

270

Using Nitrogen and Oxygen Isotope Compositions of Nitrate to Distinguish Contaminant Sources in Hanford Soil and Groundwater  

SciTech Connect

The nitrogen ({delta}{sup 15}N) and oxygen ({delta}{sup 18}O) isotopic compositions of nitrate in the environment are primarily a function of the source of the nitrate. The ranges of isotopic compositions for nitrate resulting from common sources are outlined in Figure 1 from Kendall (1998). As noted on Figure 1, processes such as microbial metabolism can modify the isotopic compositions of the nitrate, but the effects of these processes are generally predictable. At Hanford, nitrate and other nitrogenous compounds were significant components of most of the chemical processes used at the site. Most of the oxygen in nitrate chemicals (e.g., nitric acid) is derived from atmospheric oxygen, giving it a significantly higher {delta}{sup 18}O value (+23.5{per_thousand}) than naturally occurring nitrate that obtains most of its oxygen from water (the {delta}{sup 18}O of Hanford groundwater ranges from -14{per_thousand} to -18{per_thousand}). This makes it possible to differentiate nitrate from Hanford site activities from background nitrate at the site (including most fertilizers that might have been used prior to the Department of Energy plutonium production activities at the site). In addition, the extreme thermal and chemical conditions that occurred during some of the waste processing procedures and subsequent waste storage in select single-shell tanks resulted in unique nitrate isotopic compositions that can be used to identify those waste streams in soil and groundwater at the site (Singleton et al., 2005; Christensen et al., 2007). This report presents nitrate isotope data for soil and groundwater samples from the Hanford 200 Areas and discusses the implications of that data for potential sources of groundwater contamination.

Conrad, Mark; Bill, Markus

2008-08-01

271

Chemical and Radiochemical Composition of Thermally Stabilized Plutonium Oxide from the Plutonium Finishing Plant Considered as Alternate Feedstock for the Mixed Oxide Fuel Fabrication Facility  

SciTech Connect

Eighteen plutonium oxide samples originating from the Plutonium Finishing Plant (PFP) on the Hanford Site were analyzed to provide additional data on the suitability of PFP thermally stabilized plutonium oxides and Rocky Flats oxides as alternate feedstock to the Mixed Oxide Fuel Fabrication Facility (MFFF). Radiochemical and chemical analyses were performed on fusions, acid leaches, and water leaches of these 18 samples. The results from these destructive analyses were compared with nondestructive analyses (NDA) performed at PFP and the acceptance criteria for the alternate feedstock. The plutonium oxide materials considered as alternate feedstock at Hanford originated from several different sources including Rocky Flats oxide, scrap from the Remote Mechanical C-Line (RMC) and the Plutonium Reclamation Facility (PRF), and materials from other plutonium conversion processes at Hanford. These materials were received at PFP as metals, oxides, and solutions. All of the material considered as alternate feedstock was converted to PuO2 and thermally stabilized by heating the PuO2 powder at 950 C in an oxidizing environment. The two samples from solutions were converted to PuO2 by precipitation with Mg(OH)2. The 18 plutonium oxide samples were grouped into four categories based on their origin. The Rocky Flats oxide was divided into two categories, low- and high-chloride Rocky Flats oxides. The other two categories were PRF/RMC scrap oxides, which included scrap from both process lines and oxides produced from solutions. The two solution samples came from samples that were being tested at Pacific Northwest National Laboratory because all of the plutonium oxide from solutions at PFP had already been processed and placed in 3013 containers. These samples originated at the PFP and are from plutonium nitrate product and double-pass filtrate solutions after they had been thermally stabilized. The other 16 samples originated from thermal stabilization batches before canning at PFP. Samples varied in appearance depending on the original source of material. Rocky Flats items were mostly dark olive green with clumps that crushed easily with a mortar and pestle. PRF/RMC items showed more variability. These items were mostly rust colored. One sample contained white particles that were difficult to crush, and another sample was a dark grey with a mixture of fines and large, hard fragments. The appearance and feel of the fragments indicated they might be an alloy. The color of the solution samples was indicative of the impurities in the sample. The double-pass filtrate solution was a brown color indicative of the iron impurities in the sample. The other solution sample was light gray in color. Radiochemical analyses, including thermal ionization mass spectrometry (TIMS), alpha and gamma energy analysis (AEA and GEA), and kinetic phosphorescence analysis (KPA), indicate that these materials are all weapons-grade plutonium with consistent plutonium isotopics. A small amount of uranium (<0.14 wt%) is also present in these samples. The isotopic composition of the uranium varied widely but was consistent among each category of material. The primary water-soluble anions in these samples were Cl-, NO3-, SO42-, and PO43-. The only major anion observed in the Rocky Flats materials was Cl-, but the PRF/RMC samples had significant quantities of all of the primary anions observed. Prompt gamma measurements provide a representative analysis of the Cl- concentration in the bulk material. The primary anions observed in the solution samples were NO3-, and PO43-. The concentration of these anions did not exceed the mixed oxide (MOX) specification limits. Cations that exceeded the MOX specification limits included Cr, Fe, Ni, Al, Cu, and Si. All of the samples exceeded at least the 75% specification limit in one element.

Tingey, Joel M.; Jones, Susan A.

2005-07-01

272

Winter Wheat and Maize Response to Urea Ammonium Nitrate and a New Urea Formaldehyde Polymer Fertilizer  

Technology Transfer Automated Retrieval System (TEKTRAN)

Slow release nitrogen (N) fertilizers have potential to improve yield and nitrogen use efficiency (NUE) in winter wheat (Triticum aestivum L.) and maize (Zea mays L.). A slow release urea formaldehyde polymer (UFP) was compared with conventional aqueous urea-ammonium nitrate (UAN) [(NH2)2CO, NH4NO3]...

273

THE COEXTRACTION OF NITRIC ACID AND URANYL NITRATE BY TRIBUTYL PHOSPHATE  

Microsoft Academic Search

The most satisfactory method for the determination of nitric acid in the ; presence of uranyl nitrate was the sodium oxalate complexing of uranium. The ; determinaiion of nitric acid in the organic phase was carried out by back ; extraction into a constant volume of water, addition of 2% sodium oxalate ; solution to the aqueous backwash, and titration

T Sato

1959-01-01

274

Pyrochemical process for extracting plutonium from an electrolyte salt  

DOEpatents

A pyrochemical process for extracting plutonium from a plutonium-bearing salt is disclosed. The process is particularly useful in the recovery of plutonium from electrolyte salts which are left over from the electrorefining of plutonium. In accordance with the process, the plutonium-bearing salt is melted and mixed with metallic calcium. The calcium reduces ionized plutonium in the salt to plutonium metal, and also causes metallic plutonium in the salt, which is typically present as finely dispersed metallic shot, to coalesce. The reduced and coalesced plutonium separates out on the bottom of the reaction vessel as a separate metallic phase which is readily separable from the overlying salt upon cooling of the mixture. Yields of plutonium are typically on the order of 95%. The stripped salt is virtually free of plutonium and may be discarded to low-level waste storage.

Mullins, Lawrence J. (Los Alamos, NM); Christensen, Dana C. (Los Alamos, NM)

1984-01-01

275

Pyrochemical process for extracting plutonium from an electrolyte salt  

DOEpatents

A pyrochemical process for extracting plutonium from a plutonium-bearing salt is disclosed. The process is particularly useful in the recovery of plutonium for electrolyte salts which are left over from the electrorefining of plutonium. In accordance with the process, the plutonium-bearing salt is melted and mixed with metallic calcium. The calcium reduces ionized plutonium in the salt to plutonium metal, and also causes metallic plutonium in the salt, which is typically present as finely dispersed metallic shot, to coalesce. The reduced and coalesced plutonium separates out on the bottom of the reaction vessel as a separate metallic phase which is readily separable from the overlying salt upon cooling of the mixture. Yields of plutonium are typically on the order of 95%. The stripped salt is virtually free of plutonium and may be discarded to low-level waste storage.

Mullins, L.J.; Christensen, D.C.

1982-09-20

276

Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes  

SciTech Connect

The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

2013-09-24

277

Plutonium Immobilization Project -- Robotic canister loading  

SciTech Connect

The Plutonium Immobilization Program (PIP) is a joint venture between the Savannah River Site, Lawrence Livermore National Laboratory, Argonne National Laboratory, and Pacific Northwest National Laboratory. When operational in 2008, the PIP will fulfill the nation's nonproliferation commitment by placing surplus weapons-grade plutonium in a permanently stable ceramic form.

Hamilton, L.

2000-04-28

278

Accelerator mass spectrometry of plutonium isotopes  

Microsoft Academic Search

The feasibility of measuring plutonium isotope ratios by accelerator mass spectrometry has been demonstrated. Measurements on a test sample of known composition and on a blank showed that isotope ratios could be determined quantitatively, and that the present limit of detection by AMS is ? 106 atoms of plutonium. For 239Pu, this limit is at least two orders of magnitude

L. K. Fifield; R. G. Cresswell; M. L. di Tada; T. R. Ophel; J. P. Day; A. P. Clacher; S. J. King; N. D. Priest

1996-01-01

279

Nitrate concentrations under irrigated agriculture  

USGS Publications Warehouse

In recent years, considerable interest has been expressed in the nitrate content of water supplies. The most notable toxic effect of nitrate is infant methemoglobinemia. The risk of this disease increases significantly at nitrate-nitrogen levels exceeding 10 mg/l. For this reason, this concentration has been established as a limit for drinking water in many countries. In natural waters, nitrate is a minor ionic constituent and seldom accounts for more than a few percent of the total anions. However, nitrate in a significant concentration may occur in the vicinity of some point sources such as septic tanks, manure pits, and waste-disposal sites. Non-point sources contributing to groundwater pollution are numerous and a majority of them are related to agricultural activities. The largest single anthropogenic input of nitrate into the groundwater is fertilizer. Even though it has not been proven that nitrogen fertilizers are responsible for much of nitrate pollution, they are generally recognized as the main threat to groundwater quality, especially when inefficiently applied to irrigated fields on sandy soils. The biggest challenge facing today's agriculture is to maintain the balance between the enhancement of crop productivity and the risk of groundwater pollution. ?? 1982 Springer-Verlag New York Inc.

Zaporozec, A.

1983-01-01

280

REMOVAL OF LEGACY PLUTONIUM MATERIALS FROM SWEDEN  

SciTech Connect

U.S. Department of Energy’s National Nuclear Security Administration (NNSA) Office of Global Threat Reduction (GTRI) recently removed legacy plutonium materials from Sweden in collaboration with AB SVAFO, Sweden. This paper details the activities undertaken through the U.S. receiving site (Savannah River Site (SRS)) to support the characterization, stabilization, packaging and removal of legacy plutonium materials from Sweden in 2012. This effort was undertaken as part of GTRI’s Gap Materials Program and culminated with the successful removal of plutonium from Sweden as announced at the 2012 Nuclear Security Summit. The removal and shipment of plutonium materials to the United States was the first of its kind under NNSA’s Global Threat Reduction Initiative. The Environmental Assessment for the U.S. receipt of gap plutonium material was approved in May 2010. Since then, the multi-year process yielded many first time accomplishments associated with plutonium packaging and transport activities including the application of the of DOE-STD-3013 stabilization requirements to treat plutonium materials outside the U.S., the development of an acceptance criteria for receipt of plutonium from a foreign country, the development and application of a versatile process flow sheet for the packaging of legacy plutonium materials, the identification of a plutonium container configuration, the first international certificate validation of the 9975 shipping package and the first intercontinental shipment using the 9975 shipping package. This paper will detail the technical considerations in developing the packaging process flow sheet, defining the key elements of the flow sheet and its implementation, determining the criteria used in the selection of the transport package, developing the technical basis for the package certificate amendment and the reviews with multiple licensing authorities and most importantly integrating the technical activities with the Swedish partners.

Dunn, Kerry A. [Savannah River National Laboratory; Bellamy, J. Steve [Savannah River National Laboratory; Chandler, Greg T. [Savannah River National Laboratory; Iyer, Natraj C. [U.S. Department of Energy, National Nuclear Security Administration, Office of; Koenig, Rich E.; Leduc, D. [Savannah River National Laboratory; Hackney, B. [Savannah River National Laboratory; Leduc, Dan R. [Savannah River National Laboratory

2013-08-18

281

Plutonium and americium sorption from an EDTA complex by manganese oxide  

SciTech Connect

Studies at Oak Ridge National Laboratory indicate that trace quantities of certain actinide elements are migrating from waste disposal trenches in part as Ethylenediaminetetraacetic Acid (EDTA) complexes. Some of the strongest actinide complexes are formed by EDTA and related chelating agents. To some extent, the actinides are sorbed by the soil and a positive correlation is observed between the concentration of manganese on the surface of the soil particles and the concentration of the sorbed actinides. While manganese oxides have long been recognized as important scavengers of trace metals in the environment, sorption of an actinide element from a strong chelated complex has not been previously indicated. Batch experiments were performed to evaluate the sorption of a plutonium-EDTA complex by manganese oxide. The manganese oxide was prepared as an amorphous coating on synthetic fibers following the procedure of Moore. The prepared fiber was contacted by several nitrate solutions containing different concentrations of calcium, sodium, and EDTA to evaluate the effect of competing cations, ionic strength of solution, and concentration of complexing agent. All solutions were spiked with approximately 10/sup -7/ molar of /sup 238/Pu. For all solutions, generally greater than 95% of the plutonium was sorbed by the manganese oxide-coated fibers after contact times of 10 minutes. In all cases using the manganese oxide-coated fibers, after 100 minutes of contact time, greater than 99% of the plutonium was removed from solution. For one experiment using a solution spiked with approximately 10/sup -7/ molar of /sup 241/Am, sorption of americium was found to be significantly slower than sorption of plutonium. Greater than 99% of the americium was removed from the solution only after approximately 10,000 minutes. Although the mechanism has not been established, manganese oxide was shown to sorb plutonium and americium from, or as, an EDTA complex. 22 references, 5 figures.

Kasper, R.B.; Delegard, C.H.

1984-01-01

282

Plutonium Uptake and Distribution in Mammalian Cells: Molecular vs Polymeric Plutonium  

PubMed Central

Purpose To study the cellular responses to molecular and polymeric forms of plutonium using PC12 cells derived from rat adrenal glands. Materials and methods Serum starved PC12 cells were exposed to polymeric and molecular forms of plutonium for three hours. Cells were washed with 10 mM EGTA, 100 mM NaCl at pH 7.4 to remove surface sorbed plutonium. Localization of plutonium in individual cell was quantitatively analyzed by synchrotron X-ray fluorescence (XRF) microscopy. Results Molecular plutonium complexes introduced to cell growth media in the form of NTA, citrate, or transferrin complexes were taken up by PC12 cells, and mostly co-localized with iron within the cells. Polymeric plutonium prepared separately was not internalized by PC12 cells but it was always found on the cell surface as big agglomerates; however polymeric plutonium formed in situ was mostly found within the cells as agglomerates. Conclusions PC12 cells can differentiate molecular and polymeric forms of plutonium. Molecular plutonium is taken up by PC12 cells and mostly co-localized with iron but aged polymeric plutonium is not internalized by the cells. PMID:21770702

ARYAL, BAIKUNTHA P.; GORMAN-LEWIS, DREW; PAUNESKU, TATJANA; WILSON, RICHARD E.; LAI, BARRY; VOGT, STEFAN; WOLOSCHAK, GAYLE E.; JENSEN, MARK P.

2013-01-01

283

Synthesis of nano-structured polypyrrole/copper electrodes for nitrate and nitrite electroreduction  

NASA Astrophysics Data System (ADS)

Nanostructured polypyrrole film was synthesized onto a copper electrode in solutions of oxalic and salicylic acids and their buffers. The electrooxidation of pyrrole to form polypyrrole film and the electroreduction of nitrate and nitrite ions at synthesized Ppy modified copper electrodes (Ppy/Cu) in potassium chloride aqueous solutions were studied using chronoamperometry. The nanoporous structure of the synthesized Ppy films was characterized by scanning electron microscopy (SEM). Nitrate and nitrite reduction were performed by an electrochemical method under potentiostatic conditions. The Ppy/Cu electrodes prepared in the oxalate buffer and salicylic acid solutions perform more stable catalytic activity for nitrate reduction; their service life is about ten times longer than that for the electrodes prepared in oxalic acid solution. After 20?h of electrolysis, the nitrite was reduced completely with 100% efficiency and the nitrate was reduced with 35% efficiency. Report submitted to the 5th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN, Hanoi, 9–12 November 2010.

Phuong Thoa Nguyen, Thi; Thinh Nguyen, Viet; Nguyen Bui, Nhat; Do, Duong Kim Bao; Pham, Anh Minh

2010-09-01

284

Studies of nitrate reductase in marine phytoplankton  

Microsoft Academic Search

Certain marine phytoplankton contain the enzyme nitrate rcductase when growing on nitrate, but only low levels of enzyme were found during growth with ammonium or when the nitrogen source was depleted. Netted samples of oceanic phytoplankton contained the enzyme when taken from waters with nitrate concentrations 2-10 PM. Ammonium was assimilated in preference to nitrate in phytoplankton cultures supplied with

R. W. EPPLEY; J. L. COATSWORTH; LUCIA SOLÓRZANO

1969-01-01

285

Progress in the studies of the advanced plutonium fuel assembly  

Microsoft Academic Search

A new assembly concept, designated APA (for Advanced Plutonium fuel Assembly), should make it possible to multi-recycle plutonium in pressurized water reactors. The basic idea is founded on the manufacture of a large plutonium thin annular fuel rod with an inert support, cooled on both faces. The absence of plutonium generation, combined with moderate fuel temperature should make it possible

A. Puill; J. Bergeron; M. Rohart; S. Aniel-Buchheit; A. Bergeron; P. Matheron

2001-01-01

286

Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry  

SciTech Connect

Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude – apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix – constituting the largest uncertainty in models of snowpack NO{sub x} emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NO{sub x} emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ?1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study.

Meusinger, Carl; Johnson, Matthew S. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joel, E-mail: jsavarino@lgge.obs.ujf-grenoble.fr [Univ. Grenoble Alpes, LGGE, F-38000 Grenoble (France); CNRS, LGGE, F-38000 Grenoble (France)

2014-06-28

287

Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry  

NASA Astrophysics Data System (ADS)

Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude - apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix - constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ˜1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study.

Meusinger, Carl; Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joel; Johnson, Matthew S.

2014-06-01

288

Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry.  

PubMed

Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude - apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix - constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ?1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study. PMID:24985636

Meusinger, Carl; Berhanu, Tesfaye A; Erbland, Joseph; Savarino, Joel; Johnson, Matthew S

2014-06-28

289

Nitrate Utilization by the Diatom Skeletonema costatum  

PubMed Central

Nitrate utilization has been characterized in nitrogen-deficient cells of the marine diatom Skeletonema costatum. In order to separate nitrate uptake from nitrate reduction, nitrate reductase activity was suppressed with tungstate. Neither nitrite nor the presence of amino acids in the external medium or darkness affects nitrate uptake kinetics. Ammonium strongly inhibits carrier-mediated nitrate uptake, without affecting diffusion transfer. A model is proposed for the uptake and assimilation of nitrate in S. costatum and their regulation by ammonium ions. PMID:16660653

Serra, Juan L.; Llama, Maria J.; Cadenas, Eduardo

1978-01-01

290

Iron chlorosis and nitrate reductase activity in response to Fe stress and additional nitrate in sorghum  

Microsoft Academic Search

Effect of additional nitrate supply on chlorosis development at different levels of Fe stress was examined in iron efficient and inefficient sorghum cultivars. Nitrate reductase, the enzyme primarily responsible for nitrate reduction was estimated in roots and leaves as affected by Fe stress and additional nitrate.Young leaves showed differences in chlorosis progression at Fe stress levels. Nitrate reductase activity was

D. P. Pandey

1989-01-01

291

Oxidant supply and aqueous photochemical SOA formation in cloud droplets and aqueous aerosol  

NASA Astrophysics Data System (ADS)

Many recent laboratory, field and model studies point to significant contributions to the total secondary organic aerosol (SOA) budget from aqueous phase reactions in cloud droplets and aqueous aerosol particles. Laboratory studies of the photochemical oxidation of glyoxal and methylglyoxal in the aqueous phase show a strong dependence on the initial concentration of dissolved organics, with preferential formation of large molecules (dimers, oligomers) at the high concentrations found in ambient deliquesced aerosol particles. In such experimental studies OH radicals are produced in the aqueous phase (via hydrogen peroxide photolysis) and OH radical is assumed to be the major oxidant. An explicit aqueous photooxidation mechanism has been validated, in part, based on the observed temporal evolution of organic intermediates and products in these experiments. In this work, this mechanism was incorporated into multiphase process models (box, cloud parcel) in order to further explore aqueous SOA formation in dilute cloud droplets and concentrated aerosol particles. We found that the predicted SOA mass in both aqueous phases can be comparable despite the much lower liquid water content in aerosols, where oligomer formation is favored. Direct uptake from the gas phase was the largest source of OH radicals in the aqueous phase. In-situ production through the Fenton reaction (Fe), hydrogen peroxide and nitrate photolysis were minor sources. Since phase transfer is slower than the OH(aq) consumption by organics, modeled OH(aq) concentrations were smaller by 1-2 orders of magnitude than predicted based on thermodynamic equilibrium. Our model studies suggest that, unless there are substantial additional sources of OH radical in the aqueous phase, aqueous SOA formation will be oxidant limited. Since the phase transfer rate is a function of the drop (or particle) surface area, aqueous SOA formation may occur preferentially at or near the drop/particle surface (e.g., be surface-limited) and thus add SOA mass preferentially to particle populations with higher surface/volume ratios. These model results will be compared and contrasted with aqueous sulfate formation. We will discuss our findings in the context of ambient data that might suggest a preferential aqueous SOA formation in smaller (high surface/volume) particles. We will also highlight current gaps in our understanding of oxidant production and cycling in the aqueous phase that might influence our results and change dependencies on bulk water volume versus surface area.

Turpin, B. J.; Ervens, B.; Lim, Y. B.

2012-12-01

292

Crevice Repassivation Potential of Alloy 22 in High-Nitrate Dust Deliquescence Type Environments  

SciTech Connect

The nitrate ion (NO{sub 3}{sup -}) is an inhibitor for crevice corrosion of Alloy 22 (N06022) in chloride (Cl{sup -}) aqueous solutions. Naturally formed electrolytes may contain both chloride and nitrate ions. The higher the ratio R = [NO{sub 3}{sup -}]/[Cl{sup -}] in the solution the stronger the inhibition of crevice corrosion. Atmospheric desert dust contains both chloride and nitrate salts, generally based on sodium (Na{sup +}) and potassium (K{sup +}). Some of these salts may deliquescence at relatively low humidity at temperatures on the order of 150 C and higher. The resulting deliquescent brines are highly concentrated and especially rich in nitrate. Electrochemical tests have been performed to explore the anodic behavior of Alloy 22 in high chloride high nitrate electrolytes at temperatures as high as 150 C at ambient atmospheres. Naturally formed brines at temperatures higher than 120 C do not induce crevice corrosion in Alloy 22 because they contain high levels of nitrate. The inhibitive effect of nitrate on crevice corrosion is still active for temperatures higher than 100 C.

Lian, T; Gdowski, G E; Hailey, P D; Rebak, R B

2007-02-08

293

Effect of surface property of activated carbon on adsorption of nitrate ion.  

PubMed

In this study, the removal of acidic functional groups and introduction of basic groups/sites on activated carbons (ACs) by outgassing and ammonia gas treatment were respectively carried out to enhance the nitrate ion adsorption in aqueous solution. Then, the relationships between nitrate ion adsorption and solution pH as well as surface charge of AC were investigated to understand the basic mechanisms of nitrate ion adsorption by AC. The result showed that the nitrate ion adsorption depended on the equilibrium solution pH (pHe) and the adsorption amount was promoted with decreasing pHe. The ACs treated by outgassing and ammonia gas treatment showed larger amount of nitrate ion adsorption than that by untreated AC. These results indicated that, since basic groups/sites could adsorb protons in the solution, the AC surface would be charged positively, and that the nitrate ion would be electrically interacted with positively charged carbon surface. Accordingly, it was concluded that basic groups/sites on the surface of AC could promote nitrate ion adsorption. PMID:24189304

Iida, Tatsuya; Amano, Yoshimasa; Machida, Motoi; Imazeki, Fumio

2013-01-01

294

Electrochemical nitration of single-wall carbon nanotubes  

NASA Astrophysics Data System (ADS)

Electrochemical nitration of self-assembled single wall carbon nanotube (SWNT) sheets with -NO 2 groups is reported. A SWNT sheet, used as the working electrode in 6 M aqueous solution of potassium nitrite, was anodically oxidized to form -NO 2 groups on the SWNTs. Attenuated-total-reflection Fourier-transform infrared and micro-Raman spectroscopy showed the presence of chemisorbed -NO 2 groups consistent with transmission electron microscope images of the nanotube bundles after functionalization. Approximately 13% weight loss attributed to C-NO 2 bond breaking was measured by thermogravimetry, corresponding to an endothermic dissociation process measured by differential thermal analysis with an onset temperature near 425 °C.

Wang, Yubing; Malhotra, Sanjay V.; Owens, Frank J.; Iqbal, Zafar

2005-05-01

295

Alpaca plant poisonings: nitrate-nitrite and possible cyanide.  

PubMed

Nitrate-nitrite poisoning killed four adult alpacas and induced the abortion of a full-term fetus after access to oaten hay (Avena sativa) containing 3.2% KNO(3) equivalent in dry matter. Necropsy findings were cyanosis, dark-coloured blood, and pulmonary congestion and oedema. Aqueous humour from two adults contained 25 mg NO(3)/L and that from the fetus contained 10 mg NO(3)/L. Cyanide poisoning possibly killed two adult wether alpacas that ate a garden-cultivated variety of Osteospermum ecklonis (South African daisy, bietou) with a cyanide potential of 6800 mg HCN/kg dry matter. PMID:19245625

McKenzie, Ra; Gordon, An; Burren, Bg; Gibson, Ja; Gardner, Mp

2009-03-01

296

Mechanism of enhanced nitrate reduction via micro-electrolysis at the powdered zero-valent iron/activated carbon interface.  

PubMed

Nitrate reduction by zero-valent iron (Fe(0)) powder always works well only at controlled pH lower than 4 due to the formation of iron (hydr)oxides on its surface. Fe(0) powder combined with activated carbon (AC), i.e., Fe(0)/AC micro-electrolysis system, was first introduced to enhance nitrate reduction in aqueous solution. Comparative study was carried out to investigate nitrate reduction by Fe(0)/AC system and Fe(0) under near-neutral conditions, showing that the Fe(0)/AC system successfully reduced nitrate even at initial pH 6 with the reduction efficiency of up to 73%, whereas for Fe(0) only ?10%. The effect of Fe(0) to AC mass ratio on nitrate reduction efficiency was examined. Easier nitrate reduction was achieved with more contact between Fe(0) and AC as the result of decreasing Fe(0) to AC mass ratio. Ferrous ion and oxidation-reduction potential were measured to understand the mechanism of enhanced nitrate reduction by Fe(0)/AC micro-electrolysis. The results suggest that a relative potential difference drives much more electrons from Fe(0) to AC, thus generating adsorbed atomic hydrogen which makes it possible for nitrate to be reduced at near-neural pH. Fe(0)/AC micro-electrolysis thus presents a great potential for practical application in nitrate wastewater treatment without excessive pH adjustment. PMID:25217726

Luo, Jinghuan; Song, Guangyu; Liu, Jianyong; Qian, Guangren; Xu, Zhi Ping

2014-12-01

297

Plutonium Immobilization Can Loading Conceptual Design  

SciTech Connect

'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

Kriikku, E.

1999-05-13

298

Nitrate transport is independent of NADH and NAD(P)H nitrate reductases in barley seedlings  

NASA Technical Reports Server (NTRS)

Barley (Hordeum vulgare L.) has NADH-specific and NAD(P)H-bispecific nitrate reductase isozymes. Four isogenic lines with different nitrate reductase isozyme combinations were used to determine the role of NADH and NAD(P)H nitrate reductases on nitrate transport and assimilation in barley seedlings. Both nitrate reductase isozymes were induced by nitrate and were required for maximum nitrate assimilation in barley seedlings. Genotypes lacking the NADH isozyme (Az12) or the NAD(P)H isozyme (Az70) assimilated 65 or 85%, respectively, as much nitrate as the wild type. Nitrate assimilation by genotype (Az12;Az70) which is deficient in both nitrate reductases, was only 13% of the wild type indicating that the NADH and NAD(P)H nitrate reductase isozymes are responsible for most of the nitrate reduction in barley seedlings. For all genotypes, nitrate assimilation rates in the dark were about 55% of the rates in light. Hypotheses that nitrate reductase has direct or indirect roles in nitrate uptake were not supported by this study. Induction of nitrate transporters and the kinetics of net nitrate uptake were the same for all four genotypes indicating that neither nitrate reductase isozyme has a direct role in nitrate uptake in barley seedlings.

Warner, R. L.; Huffaker, R. C.

1989-01-01

299

Weapons-grade plutonium dispositioning. Volume 4. Plutonium dispositioning in light water reactors  

SciTech Connect

This study is in response to a request by the Reactor Panel Subcommittee of the National Academy of Sciences (NAS) Committee on International Security and Arms Control (CISAC) to evaluate the feasibility of using plutonium fuels (without uranium) for disposal in existing conventional or advanced light water reactor (LWR) designs and in low temperature/pressure LWR designs that might be developed for plutonium disposal. Three plutonium-based fuel forms (oxides, aluminum metallics, and carbides) are evaluated for neutronic performance, fabrication technology, and material and compatibility issues. For the carbides, only the fabrication technologies are addressed. Viable plutonium oxide fuels for conventional or advanced LWRs include plutonium-zirconium-calcium oxide (PuO{sub 2}-ZrO{sub 2}-CaO) with the addition of thorium oxide (ThO{sub 2}) or a burnable poison such as erbium oxide (Er{sub 2}O{sub 3}) or europium oxide (Eu{sub 2}O{sub 3}) to achieve acceptable neutronic performance. Thorium will breed fissile uranium that may be unacceptable from a proliferation standpoint. Fabrication of uranium and mixed uranium-plutonium oxide fuels is well established; however, fabrication of plutonium-based oxide fuels will require further development. Viable aluminum-plutonium metallic fuels for a low temperature/pressure LWR include plutonium aluminide in an aluminum matrix (PuAl{sub 4}-Al) with the addition of a burnable poison such as erbium (Er) or europium (Eu). Fabrication of low-enriched plutonium in aluminum-plutonium metallic fuel rods was initially established 30 years ago and will require development to recapture and adapt the technology to meet current environmental and safety regulations. Fabrication of high-enriched uranium plate fuel by the picture-frame process is a well established process, but the use of plutonium would require the process to be upgraded in the United States to conform with current regulations and minimize the waste streams.

Sterbentz, J.W.; Olsen, C.S.; Sinha, U.P.

1993-06-01

300

XPS-AES characterization of plutonium oxides and oxide carbide. The existence of plutonium monoxide  

Microsoft Academic Search

The plutonium-oxygen phase diagrams has been clarified by XPS and AES results which show that three oxygen-containing plutonium phases, PuOâ, ..cap alpha..-PuâOâ, and PuO\\/sub x\\/C\\/sub y\\/, are successively formed when oxide-coated plutonium metal is heated in vacuo to 500°C. Formation of the oxide carbide is evidenced by the fact that a shift in the Pu(4fââ) binding energy is coincident with

D. T. Larson; John M. Haschke

1981-01-01

301

Hydride-catalyzed corrosion of plutonium by air: Initiation by plutonium monoxide monohydride  

Microsoft Academic Search

Chemistry and kinetics of air reactions with plutonium monoxide monohydride (PuOH) and with mixtures of the oxide hydride and plutonium metal are defined by results of pressure-volume-temperature (PVT) measurements. Test with specimens prepared by total and partial corrosion of plutonium in 0.05 M sodium chloride solution show that reaction of residual water continues to generate Hâ after liquid water is

T. H. Allen; J. M. Haschke

1998-01-01

302

Estimated discard limits for plutonium-238 recovery processing in the plutonium processing building  

Microsoft Academic Search

This manual is intended as a basis for plutonium-238 recovery costs and as a guide for removal of plutonium-bearing wastes from the gloveboxes to be safely and economically discarded. Waste materials contaminated with plutonium-238 are generated from in-house production, analytical, process development, recovery and receipts from off-site. The contaminated materials include paper, rags, alpha-box gloves, piping, valves, filters, etc. General

D. F. Luthy; W. H. Bond

1975-01-01

303

Sorption/Desorption Interactions of Plutonium with Montmorillonite  

NASA Astrophysics Data System (ADS)

Plutonium (Pu) release to the environment through nuclear weapon development and the nuclear fuel cycle is an unfortunate legacy of the nuclear age. In part due to public health concerns over the risk of Pu contamination of drinking water, predicting the behavior of Pu in both surface and sub-surface water is a topic of continued interest. Typically it was assumed that Pu mobility in groundwater would be severely restricted, as laboratory adsorption studies commonly show that naturally occurring minerals can effectively remove plutonium from solution. However, evidence for the transport of Pu over significant distances at field sites highlights a relative lack of understanding of the fundamental processes controlling plutonium behavior in natural systems. At several field locations, enhanced mobility is due to Pu association with colloidal particles that serve to increase the transport of sorbed contaminants (Kersting et al., 1999; Santschi et al., 2002, Novikov et al., 2006). The ability for mineral colloids to transport Pu is in part controlled by its oxidation state and the rate of plutonium adsorption to, and desorption from, the mineral surface. Previously we have investigated the adsorption affinity of Pu for montmorillonite colloids, finding affinities to be similar over a wide range of Pu concentrations. In the present study we examine the stability of adsorbed Pu on the mineral surface. Pu(IV) at an initial concentration of 10-10 M was pre-equilibrated with montmorillonite in a background electrolyte at pH values of 4, 6 and 8. Following equilibration, aliquots of the suspensions were placed in a flow cell and Pu-free background electrolyte at the relevant pH was passed through the system. Flow rates were varied in order to investigate the kinetics of desorption and hence gain a mechanistic understanding of the desorption process. The flow cell experiments demonstrate that desorption of Pu from the montmorillonite surface cannot be modeled as a simple first order process. Furthermore, a pH dependence was observed, with less desorbed at pH 4 compared to pH 8. We suggest the pH dependence is likely controlled by reoxidation of Pu(IV) to Pu(V) and aqueous speciation. We will present models used to describe desorption behavior and discuss the implications for Pu transport. References: Kersting, A.B.; Efurd, D.W.; Finnegan, D.L.; Rokop, D.J.; Smith, D.K.; Thompson J.L. (1999) Migration of plutonium in groundwater at the Nevada Test Site, Nature, 397, 56-59. Novikov A.P.; Kalmykov, S.N.; Utsunomiya, S.; Ewing, R.C.; Horreard, F.; Merkulov, A.; Clark, S.B.; Tkachev, V.V.; Myasoedov, B.F. (2006) Colloid transport of plutonium in the far-field of the Mayak Production Association, Russia, Science, 314, 638-641. Santschi, P.H.; Roberts, K.; Guo, L. (2002) The organic nature of colloidal actinides transported in surface water environments. Environ. Sci. Technol., 36, 3711-3719. This work was funded by U. S. DOE Office of Biological & Environmental Sciences, Subsurface Biogeochemistry Research Program, and performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344. LLNL-ABS-570161

Begg, J.; Zavarin, M.; Zhao, P.; Kersting, A. B.

2012-12-01

304

PLUTONIUM METALLOGRAPHY AT LOS ALAMOS  

SciTech Connect

From early days of the Manhattan program to today, scientists and engineers have continued to investigate the metallurgical properties of plutonium (Pu). Although issues like aging was not a concern to the early pioneers, today the reliability of our aging stockpile is of major focus. And as the country moves toward a new generation of weapons similar problems that the early pioneers faced such as compatibility, homogeneity and malleability have come to the forefront. And metallography will continue to be a principle tool for the resolution of old and new issues. Standard metallographic techniques are used for the preparation of plutonium samples. The samples are first cut with a slow speed idamond saw. After mounting in Epon 815 epoxy resin, the samples are ground through 600 grit silicon carbide paper. PF 5070 (a Freon substitute) is used as a coolant, lubricant, and solvent for most operations. Rough mechanical polished is done with 9-{mu} diamond using a nap less cloth, for example nylon or cotton. Final polish is done with 1-{mu} diamond on a nappy cloth such as sylvet. Ethyl alcohol is then used ultrasonically to clean the samples before electro polishing. The sample is then electro-polished and etched in an electrolyte containing 10% nitric acid, and 90% dimethyleneformalmide. Ethyl alcohol is used as a final cleaning agent. Although standard metallographic preparation techniques are used, there are several reasons why metallography of Pu is difficult and challenging. Firstly, because of the health hazards associated with its radioactive properties, sample preparation is conducted in glove boxes. Figure 1 shows the metallography line, in an R and D facility. Since they are designed to be negative in pressure to the laboratory, cross-contamination of abrasives is a major problem. In addition, because of safety concerns and waste issues, there is a limit to the amount of solvent that can be used. Secondly, Pu will readily hydride or oxidize when in contact with metallographic polishing lubricants, solvents, or chemicals. And water being one of the most reactive solutions, is not used in the preparation. Figure 2 shows an example of a plutonium sample in which an oxide film has formed on the surface due to overexposure to solutions. it has been noted that nucleation of the hydride/oxide begins around inclusions and samples with a higher concentration of impurities seem to be more susceptible to this reaction. Figure 3 shows examples of small oxide rings, forming around inclusions. Lastly, during the cutting, grinding, or polishing process there is enough stress induced in the sample that the surface can transform from the soft face-centered-cubic delta phase (30 HV) to the strain-induced monoclinic alpha{prime} phase (300 HV). Figure 4 and 5 shows cross-sectional views of samples in which one was cut using a diamond saw and the other was processed through 600 grit. The white layers on the edges is the strain induced alpha{prime} phase. The 'V' shape indentation in Figure 5 was caused by a coarser abrasive which resulted in transformations to a depth of approximately 20 {micro}m. Another example of the transformation sensitivity of plutonium can be seen in Figure 6, in which the delta phase has partly transformed to alpha{prime} during micro hardness indentation.

PEREYRA, RAMIRO A. [Los Alamos National Laboratory; LOVATO, DARRYL [Los Alamos National Laboratory

2007-01-08

305

Preparation of thin ceramic films via an aqueous solution route  

DOEpatents

A new chemical method of forming thin ceramic films has been developed. An aqueous solution of metal nitrates or other soluble metal salts and a low molecular weight amino acid is coated onto a substrate and pyrolyzed. The amino acid serves to prevent precipitation of individual solution components, forming a very viscous, glass-like material as excess water is evaporated. Using metal nitrates and glycine, the method has been demonstrated for zirconia with various levels of yttria stabilization, for lanthanum-strontium chromites, and for yttrium-barium-copper oxide superconductors on various substrates.

Pederson, Larry R. (Kennewick, WA); Chick, Lawrence A. (Richland, WA); Exarhos, Gregory J. (Richland, WA)

1989-01-01

306

Solvent Extraction of Plutonium(IV), Uranium(VI), and Some Fission Products with Di-n-octylsulfoxide  

Microsoft Academic Search

Extraction behavior of plutonium(IV), uranium(VI), and some fission products from aqueous nitric acid media with di-n-octylsulfoxide (DOSO) has been studied over a wide range of conditions. Both the actinides are extracted essentially completely, whereas fission product contaminants like Zr, Ru, Ce, Eu, and Sr show negligible extraction. The absorption spectra of sulfoxide extracts containing either Pu or UO2 indicate the

J. P. Shukla; S. A. Pai; M. S. Subramanian

1979-01-01

307

A Plutonium Storage Container Pressure Measurement Technique  

Microsoft Academic Search

Plutonium oxide and metal awaiting final disposition are currently stored at the Savannah River Site in crimp sealed food pack cans. Surveillances to ensure continued safe storage of the cans include periodic lid deflection measurements using a mechanical device.

Grim

2002-01-01

308

Interaction between stainless steel and plutonium metal  

SciTech Connect

Long-term storage of excess plutonium is of great concern in the U.S. as well as abroad. The current accepted configuration involves intimate contact between the stored material and an iron-bearing container such as stainless steel. While many safety scenario studies have been conducted and used in the acceptance of stainless steel containers, little information is available on the physical interaction at elevated temperatures between certain forms of stored material and the container itself. The bulk of the safety studies has focused on the ability of a package to keep the primary stainless steel containment below the plutonium-iron eutectic temperature of approximately 410 C. However, the interactions of plutonium metal with stainless steel have been of continuing interest. This paper reports on a scoping study investigating the interaction between stainless steel and plutonium metal in a pseudo diffusion couple at temperatures above the eutectic melt-point.

Dunwoody, John T [Los Alamos National Laboratory; Mason, Richard E [Los Alamos National Laboratory; Freibert, Franz J [Los Alamos National Laboratory; Willson, Stephen P [Los Alamos National Laboratory; Veirs, Douglas K [Los Alamos National Laboratory; Worl, Laura A [Los Alamos National Laboratory; Archuleta, Alonso [Los Alamos National Laboratory; Conger, Donald J [Los Alamos National Laboratory

2010-01-01

309

Plutonium finishing plant dangerous waste training plan  

SciTech Connect

This training plan describes general requirements, worker categories, and provides course descriptions for operation of the Plutonium Finish Plant (PFP) waste generation facilities, permitted treatment, storage and disposal (TSD) units, and the 90-Day Accumulation Areas.

ENTROP, G.E.

1999-05-24

310

Analysis of plutonium in soil samples  

PubMed

Procedures for analysis of plutonium in soil samples were developed using anion exchange as a purification technique. Special attention was paid to removing impurities of 228Th which interferes in 238Pu determination by alpha spectrometry. Two anion-exchange methods were compared. The determination of plutonium in soil involves the conversion of soil samples to acid-soluble form. Two methods for the extraction of plutonium from a natural reference soil were compared. The first method (a direct digestion in nitric acid) is suitable for the determination of plutonium in large amounts of sample. The second method involves microwave digestion of soil (5 g) with a mixture of HNO3, HCl and HF, and is suitable for saving time in routine determinations. Activities calculated with a reference soil matrix were in good agreement with the reference value. The microwave digestion method was applied in a study of different soil samples, and recoveries ranged between 20% and 50%. PMID:10879871

Rubio Montero MP; Martin Sanchez A; Crespo Vazquez MT; Gascon Murillo JL

2000-07-01

311

Observed changes in the mechanism and rates of Pu(V) reduction on hematite as a function of total plutonium concentration.  

PubMed

Changes in aqueous- and solid-phase plutonium oxidation states were monitored as a function of time and plutonium concentration in hematite (?-Fe2O3) suspensions containing initially Pu(V). Batch kinetic experiments were conducted at plutonium concentrations between 10(-8) and 10(-6) M at pH 5 and 0.3 g/L (9.3 m(2)/L) hematite. Surface-mediated reduction of Pu(V) was observed under all conditions studied. However, differences in the reaction kinetics demonstrate that the mechanism of Pu(V) reduction changes as a function of plutonium concentration. Adsorption of Pu(V) was found to be the rate-limiting step at plutonium concentrations less than approximately 10(-7) M Pu(V). Plutonium reduction in these systems was attributed to trace amounts of Fe(II) in the hematite structure. Reduction of Pu(V) was found to be the rate-limiting step at concentrations higher than approximately 10(-6) M Pu(V) and is attributed to the formation of PuO(2+x)·nH2O nanoparticles and the Nernstian favorability of Pu(IV) surface complexes. The reaction order with respect to plutonium concentration was found to be -0.68 ± 0.09, indicating that there is a concentration dependence in these systems. This work strongly suggests that the kinetics of experiments carried out under high plutonium concentrations (i.e., >10(-7) M Pu) cannot be directly extrapolated to environmental concentrations of plutonium. PMID:25003955

Hixon, Amy E; Powell, Brian A

2014-08-19

312

Conversion of actinide and RE oxides into nitrates and their recovery into fluids  

SciTech Connect

The conditions for uranium oxides completely convert into uranyl nitrate hexahydrate in nitrogen tetra-oxide media (75 deg. C, 0,5-3,0 MPa, [UO{sub x}]:[H{sub 2}O]:[NO{sub 2}]=1:8:6) were found out. The conversion of Pu contained simulator of oxide spent nuclear fuel of thermal reactors was successfully demonstrated. The possibility of uranium recovery up to 95% from TR SNF without plutonium separation from FP is practically showed, what corresponds with Non-proliferation Treaty. (authors)

Bondin, V.V.; Bychkov, S.I.; Efremov, I.G.; Revenko, Y.A. [Mining Chemical Combine - MCC, 53 ul. Lenina, 662972, Zheleznogorsk (Russian Federation); Babain, V.A.; Murzin, A.A.; Romanovsky, V.N; Fedorov, Y.S.; Shadrin, A.Y.; Ryabkova, N.V.; Li, E.N. [Khlopin Radium Institute - KRI, 28, 2nd Murinsky ave, 194021, St. Petersburg (Russian Federation)

2007-07-01

313

Reduction of nitrate in Shewanella  

SciTech Connect

In the genome of Shewanella oneidensis, a napDAGHB gene cluster encoding periplasmic nitrate reductase (NapA) and accessory proteins and an nrfA gene encoding periplasmic nitrite reductase (NrfA) have been identified. These two systems seem to be atypical because the genome lacks genes encoding cytoplasmic membrane electron transport proteins, NapC for NAP and NrfBCD/NrfH for NRF, respectively. Here, we present evidence that reduction of nitrate to ammonium in S. oneidensis is carried out by these atypical systems in a two-step manner. Transcriptional and mutational analyses suggest that CymA, a cytoplasmic membrane electron transport protein, is likely to be the functional replacement of both NapC and NrfH in S. oneidensis. Surprisingly, a strain devoid of napB encoding the small subunit of nitrate reductase exhibited the maximum cell density sooner than the wild type. Further characterization of this strain showed that nitrite was not detected as a free intermediate in its culture and NapB provides a fitness gain for S. oneidensis to compete for nitrate in the environments. On the basis results from mutational analyses of napA, napB, nrfA and napBnrfA in-frame deletion mutants, we propose that NapB is able to favor nitrate reduction by routing electrons to NapA exclusively.

Gao, Haichun [University of Oklahoma; Yang, Zamin Koo [ORNL; Barua, Sumitra [University of Oklahoma, Norman; Reed, SB [Pacific Northwest National Laboratory (PNNL); Nealson, Kenneth H. [University of Southern California; Fredrikson, JK [Pacific Northwest National Laboratory (PNNL); Tiedje, James [Michigan State University, East Lansing; Zhou, Jizhong [University of Oklahoma

2009-01-01

314

Nitration of the birch pollen allergen Bet v 1.0101: efficiency and site-selectivity of liquid and gaseous nitrating agents.  

PubMed

Nitration of the major birch pollen allergen Bet v 1 alters the immune responses toward this protein, but the underlying chemical mechanisms are not yet understood. Here we address the efficiency and site-selectivity of the nitration reaction of recombinant protein samples of Bet v 1.0101 with different nitrating agents relevant for laboratory investigations (tetranitromethane, TNM), for physiological processes (peroxynitrite, ONOO(-)), and for the health effects of environmental pollutants (nitrogen dioxide and ozone, O?/NO?). We determined the total tyrosine nitration degrees (ND) and the NDs of individual tyrosine residues (NDY). High-performance liquid chromatography coupled to diode array detection and HPLC coupled to high-resolution mass spectrometry analysis of intact proteins, HPLC coupled to tandem mass spectrometry analysis of tryptic peptides, and amino acid analysis of hydrolyzed samples were performed. The preferred reaction sites were tyrosine residues at the following positions in the polypeptide chain: Y83 and Y81 for TNM, Y150 for ONOO(-), and Y83 and Y158 for O?/NO?. The tyrosine residues Y83 and Y81 are located in a hydrophobic cavity, while Y150 and Y158 are located in solvent-accessible and flexible structures of the C-terminal region. The heterogeneous reaction with O?/NO? was found to be strongly dependent on the phase state of the protein. Nitration rates were about one order of magnitude higher for aqueous protein solutions (?20% per day) than for protein filter samples (?2% per day). Overall, our findings show that the kinetics and site-selectivity of nitration strongly depend on the nitrating agent and reaction conditions, which may also affect the biological function and adverse health effects of the nitrated protein. PMID:24517313

Reinmuth-Selzle, Kathrin; Ackaert, Chloé; Kampf, Christopher J; Samonig, Martin; Shiraiwa, Manabu; Kofler, Stefan; Yang, Hong; Gadermaier, Gabriele; Brandstetter, Hans; Huber, Christian G; Duschl, Albert; Oostingh, Gertie J; Pöschl, Ulrich

2014-03-01

315

Nitration of the Birch Pollen Allergen Bet v 1.0101: Efficiency and Site-Selectivity of Liquid and Gaseous Nitrating Agents  

PubMed Central

Nitration of the major birch pollen allergen Bet v 1 alters the immune responses toward this protein, but the underlying chemical mechanisms are not yet understood. Here we address the efficiency and site-selectivity of the nitration reaction of recombinant protein samples of Bet v 1.0101 with different nitrating agents relevant for laboratory investigations (tetranitromethane, TNM), for physiological processes (peroxynitrite, ONOO–), and for the health effects of environmental pollutants (nitrogen dioxide and ozone, O3/NO2). We determined the total tyrosine nitration degrees (ND) and the NDs of individual tyrosine residues (NDY). High-performance liquid chromatography coupled to diode array detection and HPLC coupled to high-resolution mass spectrometry analysis of intact proteins, HPLC coupled to tandem mass spectrometry analysis of tryptic peptides, and amino acid analysis of hydrolyzed samples were performed. The preferred reaction sites were tyrosine residues at the following positions in the polypeptide chain: Y83 and Y81 for TNM, Y150 for ONOO–, and Y83 and Y158 for O3/NO2. The tyrosine residues Y83 and Y81 are located in a hydrophobic cavity, while Y150 and Y158 are located in solvent-accessible and flexible structures of the C-terminal region. The heterogeneous reaction with O3/NO2 was found to be strongly dependent on the phase state of the protein. Nitration rates were about one order of magnitude higher for aqueous protein solutions (?20% per day) than for protein filter samples (?2% per day). Overall, our findings show that the kinetics and site-selectivity of nitration strongly depend on the nitrating agent and reaction conditions, which may also affect the biological function and adverse health effects of the nitrated protein. PMID:24517313

2014-01-01

316

Nitrate Translocation by Detopped Corn Seedlings 1  

PubMed Central

Five-day-old seedlings of corn (Ze? mays L.) grown without nitrate were decapitated and exposed to 0.5 mm KNO3 or 0.5 mm KCl in aerated solutions at 30 C. Uptake of nitrate, chloride, and potassium was determined by replacing solutions hourly and measuring their depletion. Translocation of these ions and of organic nitrogen was determined by hourly analysis of the vascular exudate. Nitrate reduction was estimated by the difference between nitrate uptake and nitrate recovered in the tissue and exudate. Nitrate uptake exhibited its usual pattern of apparent induction resulting in the development of an accelerated uptake phase. Chloride uptake remained fairly constant throughout the experimental period. Translocation of nitrate increased progressively for at least 7 hours whereas chloride translocation reached a maximum about the 3d hour and then declined to a lower rate than nitrate translocation. Nitrate uptake and translocation were restricted by anaerobiosis, by 20 and 40 C relative to 30 C, and by 0.05 mm 6-methylpurine, an RNA-synthesis inhibitor. Accumulation, reduction and translocation of nitrate had different sensitivities to all these factors. The effect of 0.05 mm 6-methylpurine was more detrimental to nitrate translocation and nitrate reduction than to nitrate uptake. Ambient nitrate, relative to chloride, enhanced the exudation volume and the translocation of organic nitrogen within 4 hours from initiation of the experiments. Translocation of nitrate and organic nitrogen decreased shortly after removal of external nitrate. The higher rates of organic nitrogen translocation which occurred during nitrate uptake indicates either (a) rapid translocation of amino acids synthesized from the entering nitrate, or (b) an accelerated rate of protein turnover and a resulting enhancement in translocation of endogenous amino acids. PMID:16659246

Ezeta, Fernando N.; Jackson, William A.

1975-01-01

317

Explosive properties of reactor?grade plutonium  

Microsoft Academic Search

The following discussion focuses on the question of whether a terrorist organization or a threshold state could make use of plutonium recovered from light?water?reactor fuel to construct a nuclear explosive device having a significantly damaging yield. Questions persist in some nonproliferation policy circles as to whether a bomb could be made from reactor?grade plutonium of high burn?up, and if so,

J. Carson Marka

1993-01-01

318

Recycle of scrap plutonium-238 oxide fuel to support future radioisotope applications  

SciTech Connect

The Nuclear Materials Technology (NMT) Division of Los Alamos National Laboratory has initiated a development program to recover & purify plutonium-238 oxide from impure feed sources in a glove box environment. A glove box line has been designed and a chemistry flowsheet developed to perform this recovery task at large scale. The initial demonstration effort focused on purification of {sup 238}PuO{sub 2} fuel by HNO{sub 3}/HF dissolution, followed by plutonium(III) oxalate precipitation and calcination to an oxide. Decontamination factors for most impurities of concern in the fuel were very good, producing {sup 238}PuO{sub 2} fuel significantly better in purity than specified by General Purpose Heat Source (GPHS) fuel powder specifications. A sufficient quantity of purified {sup 238}PuO{sub 2} fuel was recovered from the process to allow fabrication of a GPHS unit for testing. The results are encouraging for recycle of relatively impure plutonium-238 oxide and scrap residue items into fuel for useful applications. The high specific activity of plutonium-238 magnifies the consequences and concerns of radioactive waste generation. This work places an emphasis on development of waste minimization technologies to complement the aqueous processing operation. Results from experiments on neutralized solutions of plutonium-238 resulted in decontamination to about 1 millicurie/L. Combining ultrafiltration treatment with addition of a water-soluble polymer designed to coordinate Pu, allowed solutions to be decontaminated to about 1 microcurie/L. Efforts continue to develop a capability for efficient, safe, cost-effective, and environmentally acceptable methods to recover and purify {sup 238}PuO{sub 2} fuel. {copyright} {ital 1998 American Institute of Physics.}

Schulte, L.D.; Purdy, G.M.; Jarvinen, G.D. [Advanced Technology Group NMT-6, Nuclear Materials Technology Division, Mail Stop E510, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ramsey, K.; Silver, G.L.; Espinoza, J.; Rinehart, G.H. [Actinide Ceramics and Fabrication Group NMT-9, Nuclear Materials Technology Division, Mail Stop E502, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-01-01

319

Recycle of scrap plutonium-238 oxide fuel to support future radioisotope applications  

SciTech Connect

The Nuclear Materials Technology (NMT) Division of Los Alamos National Laboratory has initiated a development program to recover and purify plutonium-238 oxide from impure feed sources in a glove box environment. A glove box line has been designed and a chemistry flowsheet developed to perform this recovery task at large scale. The initial demonstration effort focused on purification of {sup 238}PuO{sub 2} fuel by HNO{sub 3}/HF dissolution, followed by plutonium(III) oxalate precipitation and calcination to an oxide. Decontamination factors for most impurities of concern in the fuel were very good, producing {sup 238}PuO{sub 2} fuel significantly better in purity than specified by General Purpose Heat Source (GPHS) fuel powder specifications. The results are encouraging for recycle of relatively impure plutonium-238 oxide and scrap residue items into fuel for useful applications. A sufficient quantity of purified {sup 238}PuO{sub 2} fuel was recovered from the process to allow fabrication of a GPHS unit for testing. The high specific activity of plutonium-238 magnifies the consequences and concerns of radioactive waste generation. This work places an emphasis on development of waste minimization technologies to complement the aqueous processing operation. Results from experiments allowing more time for neutralized solutions of plutonium-238 to precipitate resulted in decontamination to about 1 millicurie/L. Combining ultrafiltration treatment with addition of a water-soluble polymer designed to coordinate Pu, allowed solutions to be decontaminated to about 1 microcurie/L. Efforts continue to develop a capability for efficient, safe, cost-effective, and environmentally acceptable methods to recover and purify {sup 238}PuO{sub 2} fuel.

Schulte, L.D.; Espinoza, J.M.; Ramsey, K.B.; Rinehart, G.H.; Silver, G.L.; Purdy, G.M.; Jarvinen, G.D.

1997-11-01

320

Complementary technologies for verification of excess plutonium  

SciTech Connect

Three complementary measurement technologies have been identified as candidates for use in the verification of excess plutonium of weapons origin. These technologies: high-resolution gamma-ray spectroscopy, neutron multiplicity counting, and low-resolution gamma-ray spectroscopy, are mature, robust technologies. The high-resolution gamma-ray system, Pu-600, uses the 630--670 keV region of the emitted gamma-ray spectrum to determine the ratio of {sup 240}Pu to {sup 239}Pu. It is useful in verifying the presence of plutonium and the presence of weapons-grade plutonium. Neutron multiplicity counting is well suited for verifying that the plutonium is of a safeguardable quantity and is weapons-quality material, as opposed to residue or waste. In addition, multiplicity counting can independently verify the presence of plutonium by virtue of a measured neutron self-multiplication and can detect the presence of non-plutonium neutron sources. The low-resolution gamma-ray spectroscopic technique is a template method that can provide continuity of knowledge that an item that enters the a verification regime remains under the regime. In the initial verification of an item, multiple regions of the measured low-resolution spectrum form a unique, gamma-radiation-based template for the item that can be used for comparison in subsequent verifications. In this paper the authors discuss these technologies as they relate to the different attributes that could be used in a verification regime.

Langner, , D.G.; Nicholas, N.J.; Ensslin, N.; Fearey, B.L. [Los Alamos National Lab., NM (United States); Mitchell, D.J.; Marlow, K.W. [Sandia National Lab., Albuquerque, NM (United States); Luke, S.J.; Gosnell, T.B. [Lawrence Livermore National Lab., CA (United States)

1998-12-31

321

Plutonium Finishing Plant safety evaluation report  

SciTech Connect

The Plutonium Finishing Plant (PFP) previously known as the Plutonium Process and Storage Facility, or Z-Plant, was built and put into operation in 1949. Since 1949 PFP has been used for various processing missions, including plutonium purification, oxide production, metal production, parts fabrication, plutonium recovery, and the recovery of americium (Am-241). The PFP has also been used for receipt and large scale storage of plutonium scrap and product materials. The PFP Final Safety Analysis Report (FSAR) was prepared by WHC to document the hazards associated with the facility, present safety analyses of potential accident scenarios, and demonstrate the adequacy of safety class structures, systems, and components (SSCs) and operational safety requirements (OSRs) necessary to eliminate, control, or mitigate the identified hazards. Documented in this Safety Evaluation Report (SER) is DOE`s independent review and evaluation of the PFP FSAR and the basis for approval of the PFP FSAR. The evaluation is presented in a format that parallels the format of the PFP FSAR. As an aid to the reactor, a list of acronyms has been included at the beginning of this report. The DOE review concluded that the risks associated with conducting plutonium handling, processing, and storage operations within PFP facilities, as described in the PFP FSAR, are acceptable, since the accident safety analyses associated with these activities meet the WHC risk acceptance guidelines and DOE safety goals in SEN-35-91.

Not Available

1995-01-01

322

A DGT technique for plutonium bioavailability measurements.  

PubMed

The toxicity of heavy metals in natural waters is strongly dependent on the local chemical environment. Assessing the bioavailability of radionuclides predicts the toxic effects to aquatic biota. The technique of diffusive gradients in thin films (DGT) is largely exploited for bioavailability measurements of trace metals in waters. However, it has not been applied for plutonium speciation measurements yet. This study investigates the use of DGT technique for plutonium bioavailability measurements in chemically different environments. We used a diffusion cell to determine the diffusion coefficients (D) of plutonium in polyacrylamide (PAM) gel and found D in the range of 2.06-2.29 × 10(-6) cm(2) s(-1). It ranged between 1.10 and 2.03 × 10(-6) cm(2) s(-1) in the presence of fulvic acid and in natural waters with low DOM. In the presence of 20 ppm of humic acid of an organic-rich soil, plutonium diffusion was hindered by a factor of 5, with a diffusion coefficient of 0.50 × 10(-6) cm(2) s(-1). We also tested commercially available DGT devices with Chelex resin for plutonium bioavailability measurements in laboratory conditions and the diffusion coefficients agreed with those from the diffusion cell experiments. These findings show that the DGT methodology can be used to investigate the bioaccumulation of the labile plutonium fraction in aquatic biota. PMID:25141175

Cusnir, Ruslan; Steinmann, Philipp; Bochud, François; Froidevaux, Pascal

2014-09-16

323

Flow of Aqueous Humor  

MedlinePLUS

... Involved Research Grants Special Events Flow of Aqueous Humor © 2000 BrightFocus Foundation Unauthorized reprints not allowed. Most , ... remains normal when some of the fluid (aqueous humor) produced by the eye's ciliary body flows out ...

324

Short-term effects of a high nitrate diet on nitrate metabolism in healthy individuals.  

PubMed

Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake. PMID:25774606

Bondonno, Catherine P; Liu, Alex H; Croft, Kevin D; Ward, Natalie C; Puddey, Ian B; Woodman, Richard J; Hodgson, Jonathan M

2015-01-01

325

Acetonyltriphenyl­phospho­nium nitrate  

PubMed Central

Crystals of the title salt, C21H20OP+·NO3 ?, are composed of acetonyltriphenyl­phospho­nium cations and nitrate anions that mainly inter­act through electrostatic forces. The P atom in the cation has a slightly distorted tetra­hedral environment, with C—P—C angles ranging from 104.79?(7) to 112.59?(6)°. The sum of O—N—O angles of the nitrate anion is 359.99°, reflecting its trigonal–planar character. C—H?O hydrogen bonds help to consolidate the crystal packing. PMID:23424568

Diop, Tidiane; Diop, Libasse; Ku?eráková, Monika; Dušek, Michal

2013-01-01

326

[Infantile methemoglobinemia caused by nitrates].  

PubMed

The intake of water or food with high levels of nitrates produces methemoglobinemia in infants up to 3 months of age. The study reviews factors in the environment and in the host that account for the increased risk in this age group. In order to reduce the prevalence of this problem, health authorities should control nitrate concentrations in drinking water, create adequate water supply systems, implement educational programs aimed at informing parents about preventive measures, and call on physicians to report cases of methemoglobinemia. PMID:2525389

de Fernícola, N A

1989-01-01

327

What is plutonium stabilization, and what is safe storage of plutonium?  

Microsoft Academic Search

The end of the cold war has resulted in the shutdown of nuclear weapons production and the start of dismantlement of significant numbers of nuclear weapons. This, in turn, is creating an inventory of plutonium requiring interim and long-term storage. A key question is, ``What is required for safe, multidecade, plutonium storage?`` The requirements for storage, in turn, define what

1995-01-01

328

Development of plutonium recycle in thermal reactors. Evaluation of plutonium recycle in pressurized water reactors  

Microsoft Academic Search

An evaluation of the utilization of plutonium recycle fuel in the ; Obrigheim power reactor was performed in order to study the characteristics of ; typical large PWR's operated with plutonium recycle fuel. The evaluation ; included nuclear characteristics, fuel management, a thermal-hydraulic analysis, ; and an economic analysis. (JWR)

J. R. Tomonto; J. S. Tulenko; J. Fiscella; J. Ray

1969-01-01

329

Uranyl peroxide pyrophosphate cage clusters with oxalate and nitrate bridges.  

PubMed

Two complex cage clusters built from uranyl hexagonal bipyramids and multiple types of bridges between uranyl ions, U(30)Py(10)Ox(5) and U(38)Py(10)Nt(4), were crystallized from aqueous solution under ambient conditions. These are built from 30 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and five oxalate bridges in one case, and 38 uranyl hexagonal bipyramids, 10 pyrophosphate groups, and four nitrate groups in the other. The crystal compositions are (H(3)O)(10)Li(18)K(22)[(UO(2))(30)(O(2))(30)(P(2)O(7))(10)(C(2)O(4))(5)](H(2)O)(22) and Li(24)K(36)[(UO(2))(38)(O(2))(40)(OH)(8)(P(2)O(7))(10)(NO(3))(4)](NO(3))(4)(H(2)O)(n) for U(30)Py(10)Ox(5) and U(38)Py(10)Nt(4), respectively. Cluster U(30)Py(10)Ox(5) crystallizes over a narrow range of solution pH that encourages incorporation of both oxalate and pyrophosphate, with incorporation of oxalate only being favored under more acidic conditions, and pyrophosphate only under more alkaline conditions. Cluster U(38)Py(10)Nt(4) contains two identical lobes consisting of uranyl polyhedra and pyrophosphate groups, with these lobes linked into the larger cluster through four nitrate groups. The synthesis conditions appear to have prevented closure of these lobes, and a relatively high nitrate concentration in solution favored formation of the larger cluster. PMID:22569991

Ling, Jie; Ozga, Michael; Stoffer, Megan; Burns, Peter C

2012-06-28

330

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2013 CFR

...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or...

2013-04-01

331

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2012 CFR

...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or...

2012-04-01

332

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2011 CFR

...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or...

2011-04-01

333

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2010 CFR

...FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or...

2010-04-01

334

21 CFR 172.170 - Sodium nitrate.  

Code of Federal Regulations, 2014 CFR

...HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or...

2014-04-01

335

Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies.  

PubMed

The effects of dissolved organic matter (DOM) on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins. With the increase of gallic acid concentration from 0 to 400 mg/L, the adsorption amount of nitrate-nitrogen on the commercial resins, including D201, Purolite A 300 (A300) and Purolite A 520E (A520E), would significantly decrease. However, the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them.Compared to D201 and A300 resins, A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules, such as gallic acid and tannin acid at greater levels in aqueous solution. Attractively, the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Freundlich equations. The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations. In batch adsorption processes, nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time. The pseudo first- and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin. The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater. PMID:23586305

Song, Haiou; Yao, Zhijian; Wang, Mengqiao; Wang, Jinnan; Zhu, Zhaolian; Li, Aimin

2013-01-01

336

A Novel Chemical Nitrate Destruction Process  

SciTech Connect

Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

Dziewinski, J.; Marczak, S.

1999-03-01

337

Deliquescence, Efflorescence, and Water Activity in Ammonium Nitrate and Mixed Ammonium Nitrate/Succinic Acid Microparticles  

E-print Network

not take up a significant amount of water. Additionally, the deliquescence relative humidity is foundDeliquescence, Efflorescence, and Water Activity in Ammonium Nitrate and Mixed Ammonium Nitrate of ammonium nitrate/water and mixed ammonium nitrate/succinic acid/water microparticles. The water activity

338

Constructed Marshes for Nitrate Removal  

Microsoft Academic Search

Large numbers of free water surface treatment wetlands are in use for nitrate reduction. Target applications are field runoff, river and stream improvement, and enhancement of wastewater treatment plants. In total, an extensive database now exists, in many publications and operating reports. Microcosms and mesocosms are not included here because of the lack of transferability to design. A first-order areal

Robert H. Kadlec

2012-01-01

339

Constructed Marshes for Nitrate Removal  

Microsoft Academic Search

Large numbers of free water surface treatment wetlands are in use for nitrate reduction. Target applications are field runoff, river and stream improvement, and enhancement of wastewater treatment plants. In total, an extensive database now exists, in many publications and operating reports. Microcosms and mesocosms are not included here, because of lack of transferability to design. A first-order areal model

Robert H. Kadlec

2011-01-01

340

Nitration of Naphthol: A Laboratory Experiment.  

ERIC Educational Resources Information Center

Products of nitrations, upon distillation or steam distillation, may produce dermatitis in some students. A procedure for nitration of beta-naphthol producing a relatively non-volatile product not purified by steam distillation is described. Nitration of alpha-naphthol by the same procedure yields Martius Yellow dye which dyes wool yellow or…

Mowery, Dwight F.

1982-01-01

341

Efflux Of Nitrate From Hydroponically Grown Wheat  

NASA Technical Reports Server (NTRS)

Report describes experiments to measure influx, and efflux of nitrate from hydroponically grown wheat seedlings. Ratio between efflux and influx greater in darkness than in light; increased with concentration of nitrate in nutrient solution. On basis of experiments, authors suggest nutrient solution optimized at lowest possible concentration of nitrate.

Huffaker, R. C.; Aslam, M.; Ward, M. R.

1992-01-01

342

Spatial Inference of Nitrate Concentrations in Groundwater  

E-print Network

of the fine-scale estimated nitrate concentration is obtained, as well as maps of the estimated county-level average nitrate concentration and similar maps at the level of watersheds and other geographic regions levels in drinking water. Nitrate occurs naturally in groundwater, but elevated levels can be caused

West, Mike

343

3, 59195976, 2003 The nitrate aerosol  

E-print Network

was used for model evalu- ation. During winter, fall and especially spring high nitrate levels aerosols. Also, inclusion of sea salt is necessary to properly assess the nitrate and nitric acid levelsACPD 3, 5919­5976, 2003 The nitrate aerosol field over Europe M. Schaap et al. Title Page Abstract

Paris-Sud XI, Université de

344

Modeling nitrate removal in a denitrification bed  

Technology Transfer Automated Retrieval System (TEKTRAN)

Denitrification beds are being promoted to reduce nitrate concentrations in agricultural drainage water to alleviate the adverse environmental effects associated with nitrate pollution in surface water. In this system, water flows through a trench filled with a carbon media where nitrate is transfor...

345

Nitrate removal from drinking water -- Review  

Microsoft Academic Search

Nitrate concentrations in surface water and especially in ground water have increased in Canada, the US, Europe, and other areas of the world. This trend has raised concern because nitrates cause methemoglobiinemia in infants. Several treatment processes including ion exchange, biological denitrification, chemical denitrification, reverse osmosis, electrodialysis, and catalytic denitrification can remove nitrates from water with varying degrees of efficiency,

Anoop Kapoor; T. Viraraghavan

1997-01-01

346

Three nitrate reductase activities in Alcaligenes eutrophus  

Microsoft Academic Search

Three nitrate reductase activities were detected in Alcaligenes eutrophus strain H16 by physiological and mutant analysis. The first (NAS) was subject to repression by ammonia and not affected by oxygen indicating a nitrate assimilatory function. The second (NAR) membrane-bound activity was only formed in the absence of oxygen and was insensitive to ammonia repression indicating a nitrate respiratory function. The

Ute Warnecke-Eberz; Bärbel Friedrich

1993-01-01

347

SOME PHYSICAL PROPERTIES OF URANYL NITRATE SOLUTIONS  

Microsoft Academic Search

Boillng points, freezing points, and densities were measured in the ;\\u000a concentration range between uranyl nitrate hexahydrate and uranyl nitrate ;\\u000a dihydrate. The surface tension of molten uranyl nitrate hexahydrate was ;\\u000a determined to be approximately 45 dynes per square centimeter at 90 to 1OO icient ;\\u000a laborato C. (auth)

G. P. Lang; M. O. Nethaway

1958-01-01

348

DO ORGANIC FARMING PRACTICES REDUCE NITRATE LEACHING?  

Microsoft Academic Search

Agriculture is a contributor of nitrate to natural waters and there is concern about the excess nitrogen burden loadings from agriculture on natural waters. Agricultural practices that reduce nitrate leaching from arable land are needed. It is postulated by certain groups that organic farming practices reduce nitrate leaching among other environmental benefits. The objectives of this paper are: (1) to

Holger Kirchmann; Lars Bergström

2001-01-01

349

Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing  

Microsoft Academic Search

The effect of aqueous versus crystalline sulfate- nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three- dimensional chemical transport model predicts sulfate, ni- trate, and ammonium aerosol mass. An aerosol thermody- namics model is called twice, once for the upper side (US) and once for lower side (LS) of the hysteresis loop of parti- cle

S. T. Martin; H.-M. Hung; R. J. Park; D. J. Jacob; R. J. D. Spurr; K. V. Chance; M. Chin

2003-01-01

350

Polyaniline–silver composites prepared by the oxidation of aniline with silver nitrate in solutions of sulfonic acids  

Microsoft Academic Search

Aniline was oxidized with silver nitrate in aqueous solutions of sulfonic acids: camphorsulfonic, methanesulfonic, sulfamic, or toluenesulfonic acids. Polyaniline–silver composites were produced slowly in 4 weeks in good yield, except for the reaction, which took place in sulfamic acid solution, where the yield was low. Polyaniline in the emeraldine form was identified with UV–visible, FTIR, and Raman spectra. Thermogravimetric analysis

Patrycja Bober; Miroslava Trchová; Jan Prokeš; Martin Varga; Jaroslav Stejskal

2011-01-01

351

Chemical and physical properties vs degree of concentration of uranyl nitrate-nitric acid process streams of metal conversion plant  

Microsoft Academic Search

Uranium is recovered as an aqueous solution of uranyl nitrate and nitric acid in both the tributyl phosphate metal recovery process and the Redox separation process. The streams are designated as RCU and IIIEU in the respective processes. For metal recovery these streams are combined. The purpose of the nitric removal operation is to minimize equipment corrosion and to restrict

Clagett

1950-01-01

352

Behaviors of acrylamide/itaconic acid hydrogels in uptake of uranyl ions from aqueous solutions  

SciTech Connect

In this study, adsorptions of uranyl ions from two different aqueous uranyl solutions by acrylamide-itaconic acid hydrogels were investigated by a spectroscopic method. The hydrogels were prepared by irradiating with {gamma}-radiation. In the experiment of uranyl ions adsorption, Type II adsorption was found. One gram of acrylamide-itaconic acid hydrogels sorbed 178-219 mg uranyl ions from the solutions of uranyl acetate, 42-76 mg uranyl ions from the aqueous solutions of uranyl nitrate, while acrylamide hydrogel did not sorb any uranyl ion. For the hydrogel containing 40 mg of itaconic acid and irradiated to 3.73 kGy, swelling of the hydrogels was observed in water (1660%), in the aqueous solution of uranyl acetate (730%), and in the aqueous solution of uranyl nitrate (580%). Diffusions of water onto hydrogels were a non-Fickian type of diffusion, whereas diffusions of uranyl ions were a Fickian type of diffusion.

Karadag, E.; Saraydin, D. [Cumhuriyet Univ., Sivas (Turkey); Gueven, O. [Hacettepe Univ., Ankara (Turkey)

1995-12-01

353

71. INTERIOR, BUILDING 272 (PLUTONIUM STORAGE BUILDING) LOOKING NORTHEAST INTO ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

71. INTERIOR, BUILDING 272 (PLUTONIUM STORAGE BUILDING) LOOKING NORTHEAST INTO PLUTONIUM STORAGE ROOM SHOWING CUBICLES FOR STORAGE. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

354

69. INTERIOR, BUILDING 272 (PLUTONIUM STORAGE BUILDING) LOOKING SOUTHWEST THROUGH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

69. INTERIOR, BUILDING 272 (PLUTONIUM STORAGE BUILDING) LOOKING SOUTHWEST THROUGH DOOR-WAY INTO PLUTONIUM STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

355

16. VIEW OF GLOVE BOX WORKSTATIONS WITHIN THE PLUTONIUM BUTTON ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. VIEW OF GLOVE BOX WORKSTATIONS WITHIN THE PLUTONIUM BUTTON BREAKOUT ROOM. (9/82) - Rocky Flats Plant, Plutonium Recovery Facility, Northwest portion of Rocky Flats Plant, Golden, Jefferson County, CO

356

The design and evaluation of an international plutonium storage system  

E-print Network

To address the proliferation risk of separated plutonium, a technical and institutional design of an international plutonium storage system (IPSS) is presented. The IPSS is evaluated from two perspectives: its ability to ...

Bae, Eugene

2001-01-01

357

10 CFR 71.88 - Air transport of plutonium.  

Code of Federal Regulations, 2010 CFR

...to the activity concentration values for plutonium specified in Appendix A, Table A-2, of this part, and in which the radioactivity is essentially uniformly distributed; or (3) The plutonium is shipped in a single package containing no more than...

2010-01-01

358

10 CFR 71.88 - Air transport of plutonium.  

Code of Federal Regulations, 2013 CFR

...to the activity concentration values for plutonium specified in Appendix A, Table A-2, of this part, and in which the radioactivity is essentially uniformly distributed; or (3) The plutonium is shipped in a single package containing no more than...

2013-01-01

359

10 CFR 71.88 - Air transport of plutonium.  

Code of Federal Regulations, 2012 CFR

...to the activity concentration values for plutonium specified in Appendix A, Table A-2, of this part, and in which the radioactivity is essentially uniformly distributed; or (3) The plutonium is shipped in a single package containing no more than...

2012-01-01

360

10 CFR 71.88 - Air transport of plutonium.  

Code of Federal Regulations, 2011 CFR

...to the activity concentration values for plutonium specified in Appendix A, Table A-2, of this part, and in which the radioactivity is essentially uniformly distributed; or (3) The plutonium is shipped in a single package containing no more than...

2011-01-01

361

Dispersion of plutonium from contaminated pond sediments  

USGS Publications Warehouse

Sediment-water distributions of plutonium as a function of pH and contact time are investigated in a holding pond at the Rocky Flats plant of the Department of Energy. Although plutonium has been shown to sorb from natural waters onto sediments, the results of this study indicate that under the proper conditions it can be redispersed at pH 9 and above. Concentrations greater than 900 pCi Pu/L result after 34 h contact at pH 11 or 12 and the distribution coefficient, defined as the ratio of concentration in the sediment to that in the liquid, decreases from 1.1 ?? 105 at pH 7 to 1.2 ?? 103 at pH 11. The plutonium is probably dispersed as discrete colloids or as hydrolytic species adsorbed onto colloidal sediment particles whose average size decreases with increasing pH above pH 9. About 5% of the total plutonium is dispersed at pH 12, and the dispersion seems to readsorb on the sediment with time. Consequently, migration of plutonium from the pond should be slow, and it would be difficult to remove this element completely from pond sediment by leaching with high pH solutions. ?? 1978 American Chemical Society.

Rees, T.F.; Cleveland, J.M.; Carl, Gottschall W.

1978-01-01

362

EXTRACTION OF NEPTUNIUM AND PLUTONIUM NITRATES WITH n-OCTYL(PHENYL)-N,N-DIISOBUTYL-CARBAMOYLMETHYLPHOSPHINE OXIDE  

Microsoft Academic Search

Distribution equilibria of Np and Pu in various valence states and stripping of Np(V) were studied in a system involving 0.20 M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide + 1.2 M tributyl phosphate in dodecane as a solvent. Np(V) is weakly extractable at <2 M nitric acid but more effectively extractable at >3 M nitric acid, due to the disproportionation of Np(V) to Np(IV)

Zdenek J. Kolarik; E. Philip Horwitz

1988-01-01

363

Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation.  

PubMed

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake. A reevaluation of our currently very negative perception of dietary nitrates comes from recent research into the metabolism and enterosalivary circulation of nitrate in mammals. These studies showed that nitrate is converted to nitrite in the oral cavity that then "fuels" an important mammalian resistance mechanism against infectious diseases. Moreover, there is now evidence that the conversion of nitrate into oxides of nitrogen prevents the formation carcinogenic nitrosamines. PMID:9505412

Duncan, C; Li, H; Dykhuizen, R; Frazer, R; Johnston, P; MacKnight, G; Smith, L; Lamza, K; McKenzie, H; Batt, L; Kelly, D; Golden, M; Benjamin, N; Leifert, C

1997-12-01

364

Continuous flow nitration in miniaturized devices  

PubMed Central

Summary This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed. PMID:24605161

2014-01-01

365

Continuous flow nitration in miniaturized devices.  

PubMed

This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed. PMID:24605161

Kulkarni, Amol A

2014-01-01

366

Nitrated fatty acids: Synthesis and measurement  

PubMed Central

Nitrated fatty acids are the product of nitrogen dioxide reaction with unsaturated fatty acids. The discovery of peroxynitrite and peroxidase-induced nitration of biomolecules led to the initial reports of endogenous nitrated fatty acids. These species increase during ischemia reperfusion, but concentrations are often at or near the limits of detection. Here, we describe multiple methods for nitrated fatty acid synthesis, sample extraction from complex biological matrices, and a rigorous method of qualitative and quantitative detection of nitrated fatty acids by LC-MS. In addition, optimized instrument conditions and caveats regarding data interpretation are discussed. PMID:23200809

Woodcock, Steven R.; Bonacci, Gustavo; Gelhaus, Stacy L.; Schopfer, Francisco J.

2012-01-01

367

Effects of nitrate on the stability of uranium in a bioreduced region of the subsurface  

SciTech Connect

The effects of nitrate on the stability of reduced, immobilized uranium were evaluated in field experiments at a U.S. Department of Energy site in Oak Ridge, TN. Nitrate (2.0 mM) was injected into a reduced region of the subsurface containing high levels of previously immobilized U(IV). The nitrate was reduced to nitrite, ammonium, and nitrogen gas; sulfide levels decreased; and Fe(II) levels increased then deceased. Uranium remobilization occurred concomitant with nitrite formation, suggesting nitrate-dependent, iron-accelerated oxidation of U(IV). Bromide tracer results indicated changes in subsurface flowpaths likely due to gas formation and/or precipitate. Desorption-adsorption of uranium by the iron-rich sediment impacted uranium mobilization and sequestration. After rereduction of the subsurface through ethanol additions, background groundwater containing high levels of nitrate was allowed to enter the reduced test zone. Aqueous uranium concentrations increased then decreased. Clone library analyses of sediment samples revealed the presence of denitrifying bacteria that can oxidize elemental sulfur, H{sub 2}S, Fe(II), and U(IV) (e.g., Thiobacillus spp.), and a decrease in relative abundance of bacteria that can reduce Fe(III) and sulfate. XANES analyses of sediment samples confirmed changes in uranium oxidation state. Addition of ethanol restored reduced conditions and triggered a short-term increase in Fe(II) and aqueous uranium, likely due to reductive dissolution of Fe(III) oxides and release of sorbed U(VI). After two months of intermittent ethanol addition, sulfide levels increased, and aqueous uranium concentrations gradually decreased to <0.1 {mu}M.

Wu, Weimin [Stanford University; Carley, Jack M [ORNL; Green, Stefan [Florida State University, Tallahassee; Luo, Jian [Georgia Institute of Technology; Kelly, Shelly D [Argonne National Laboratory (ANL); Van Nostrand, Joy [University of Oklahoma, Norman; Lowe, Kenneth Alan [ORNL; Mehlhorn, Tonia L [ORNL; Carroll, Sue L [ORNL; Boonchayanant, Dr. Benjaporn [Stanford University; Loeffler, Frank E [ORNL; Jardine, Philip M [ORNL; Criddle, Craig [ORNL

2010-06-01

368

Complexation of lanthanides with nitrate at variable temperatures: thermodynamics and coordination modes.  

PubMed

Complexation of neodymium(III) with nitrate was studied at variable temperatures (25, 40, 55, and 70 degrees C) by spectrophotometry and microcalorimetry. The NdNO(3)(2+) complex is weak and becomes slightly stronger as the temperature is increased. The enthalpy of complexation at 25 degrees C was determined by microcalorimetry to be small and positive, 1.5 +/- 0.2 kJ x mol(-1), in good agreement with the trend of the stability constant at variable temperatures. Luminescence emission spectra and the lifetime of Eu(III) in nitrate solutions suggest that inner-sphere and bidentate complexes form between trivalent lanthanides (Nd(3+) and Eu(3+)) and nitrate in aqueous solutions. A specific ion interaction approach was used to obtain the stability constants of NdNO(3)(2+) at infinite dilution and variable temperatures. PMID:19115981

Rao, Linfeng; Tian, Guoxin

2009-02-01

369

Precipitation of plutonium from acidic solutions using magnesium oxide  

SciTech Connect

Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements.

Jones, S.A.

1994-12-05

370

15. VIEW OF THE SAFE GEOMETRY PLUTONIUM METAL STORAGE PALLETS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. VIEW OF THE SAFE GEOMETRY PLUTONIUM METAL STORAGE PALLETS FROM THE INSIDE OF AN INPUT-OUTPUT STATION. INDIVIDUAL CONTAINERS OF PLUTONIUM ARE STORED IN THE WATER-FILLED, DOUBLE-WALLED STAINLESS STEEL TUBES THAT ARE WELDED ONTO THE PALLETS. (12/3/88) - Rocky Flats Plant, Plutonium Recovery Facility, Northwest portion of Rocky Flats Plant, Golden, Jefferson County, CO

371

VIEW OF THE INTERIOR OF THE PLUTONIUM LABORATORY IN BUILDING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF THE INTERIOR OF THE PLUTONIUM LABORATORY IN BUILDING 559. THE LABORATORY WAS USED TO ANALYZE THE PURITY OF PLUTONIUM. PLUTONIUM SAMPLES WERE CONTAINED WITHIN GLOVE BOXES - Rocky Flats Plant, Chemical Analytical Laboratory, North-central section of Plant, Golden, Jefferson County, CO

372

10 CFR 71.88 - Air transport of plutonium.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Air transport of plutonium. 71.88 Section 71.88 Energy...Procedures § 71.88 Air transport of plutonium. (a) Notwithstanding the provisions...applicable, the licensee shall assure that plutonium in any form, whether for...

2014-01-01

373

Calculated Phonon Spectra of Plutonium at High Temperatures  

E-print Network

Calculated Phonon Spectra of Plutonium at High Temperatures X. Dai,1 S. Y. Savrasov,2 * G. Kotliar dynamical proper- ties of plutonium using an electronic structure method, which incorporates correlation anharmonic and can be stabilized at high temperatures by its phonon entropy. Plutonium (Pu) is a material

Savrasov, Sergej Y.

374

Application of Fusion Neutron Source for Denaturing of Plutonium  

Microsoft Academic Search

Potential of DT fusion neutron source to enhance proliferation resistance properties of plutonium by means of its isotopic denaturing is addressed. The approach is exemplified by denaturing of pure Pu and plutonium of typical LWR spent fuel through transmutation of neptunium. The essential feature of a fusion driven system proposed in the study is a zero mass balance of plutonium:

Alan TAKIBAYEV; Masaki SAITO; Hiroshi SAGARA

2007-01-01

375

REVIEW OF PLUTONIUM OXIDATION LITERATURE  

SciTech Connect

A brief review of plutonium oxidation literature was conducted. The purpose of the review was to ascertain the effect of oxidation conditions on oxide morphology to support the design and operation of the PDCF direct metal oxidation (DMO) furnace. The interest in the review was due to a new furnace design that resulted in oxide characteristics that are different than those of the original furnace. Very little of the published literature is directly relevant to the DMO furnace operation, which makes assimilation of the literature data with operating conditions and data a convoluted task. The oxidation behavior can be distilled into three regimes, a low temperature regime (RT to 350 C) with a relatively slow oxidation rate that is influenced by moisture, a moderate temperature regime (350-450 C) that is temperature dependent and relies on more or less conventional oxidation growth of a partially protective oxide scale, and high temperature oxidation (> 500 C) where the metal autocatalytically combusts and oxidizes. The particle sizes obtained from these three regimes vary with the finest being from the lowest temperature. It is surmised that the slow growth rate permits significant stress levels to be achieved that help break up the oxides. The intermediate temperatures result in a fairly compact scale that is partially protective and that grows to critical thickness prior to fracturing. The growth rate in this regime may be parabolic or paralinear, depending on the oxidation time and consequently the oxide thickness. The high temperature oxidation is invariant in quiescent or nearly quiescent conditions due to gas blanketing while it accelerates with temperature under flowing conditions. The oxide morphology will generally consist of fine particles (<15 {micro}m), moderately sized particles (15 < x < 250 {micro}m) and large particles (> 250 {micro}m). The particle size ratio is expected to be < 5%, 25%, and 70% for fine, medium and large particles, respectively, for metal temperatures in the 500-600 C range.

Korinko, P.

2009-11-12

376

Plutonium transport in the environment.  

PubMed

The recent estimated global stockpile of separated plutonium (Pu) worldwide is about 500 t, with equal contributions from nuclear weapons and civilian nuclear energy. Independent of the United States' future nuclear energy policy, the current large and increasing stockpile of Pu needs to be safely isolated from the biosphere and stored for thousands of years. Recent laboratory and field studies have demonstrated the ability of colloids (1-1000 nm particles) to facilitate the migration of strongly sorbing contaminants such as Pu. In understanding the dominant processes that may facilitate the transport of Pu, the initial source chemistry and groundwater chemistry are important factors, as no one process can explain all the different field observations of Pu transport. Very little is known about the molecular-scale geochemical and biochemical mechanisms controlling Pu transport, leaving our conceptual model incomplete. Equally uncertain are the conditions that inhibit the cycling and mobility of Pu in the subsurface. Without a better mechanistic understanding for Pu at the molecular level, we cannot advance our ability to model its transport behavior and achieve confidence in predicting long-term transport. Without a conceptual model that can successfully predict long-term Pu behavior and ultimately isolation from the biosphere, the public will remain skeptical that nuclear energy is a viable and an attractive alternative to counter global warming effects of carbon-based energy alternatives. This review summarizes our current understanding of the relevant conditions and processes controlling the behavior of Pu in the environment, gaps in our scientific knowledge, and future research needs. PMID:23458827

Kersting, Annie B

2013-04-01

377

The United States Plutonium Balance, 1944 - 2009  

SciTech Connect

This report updates the report -Plutonium: The first 50 years- which was released by the U.S.Department of Energy (DOE) in 1996. The topic of both reports is plutonium, sometimes referred to as Pu-239, which is capable of sustaining a nuclear chain reaction and is used in nuclear weapons and for nuclear power production. This report updates 1994 data through 2009. The four most significant changes since 1994 include: (a) the completion of cleanup activities at the Rocky Flats Plant in 2005; (b) material consolidation and disposition activities, especially shipments from Hanford to the Savannah River Site; (c) the 2007 declaration of an additional 9.0 MT of weapons grade plutonium to be surplus to defense needs in the coming decades; and (d) the opening of the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico in 1999.

none,

2012-06-01

378

Excess plutonium disposition: The deep borehole option  

SciTech Connect

This report reviews the current status of technologies required for the disposition of plutonium in Very Deep Holes (VDH). It is in response to a recent National Academy of Sciences (NAS) report which addressed the management of excess weapons plutonium and recommended three approaches to the ultimate disposition of excess plutonium: (1) fabrication and use as a fuel in existing or modified reactors in a once-through cycle, (2) vitrification with high-level radioactive waste for repository disposition, (3) burial in deep boreholes. As indicated in the NAS report, substantial effort would be required to address the broad range of issues related to deep bore-hole emplacement. Subjects reviewed in this report include geology and hydrology, design and engineering, safety and licensing, policy decisions that can impact the viability of the concept, and applicable international programs. Key technical areas that would require attention should decisions be made to further develop the borehole emplacement option are identified.

Ferguson, K.L.

1994-08-09

379

Computerized plutonium wound-analysis system  

SciTech Connect

A new plutonium wound monitor has been developed at Los Alamos to upgrade a system which has been in use for about five years. The instrument, called a Computerized Wound Screening System, is designed around a readily available personal computer. It includes a full-function 256-channel pulse height analyzer and software necessary to calculate plutonium and americium activity from a spectrum. This new system provides medical and health physics personnel with considerable flexability in recognizing and recording situations where a wound incurred in a plutonium processing facility might be contaminated. This flexibility includes fast, accurate determination of contaminants in a wound, hard copy printout of results, and full patient logging capabilities via flexible disk storage. Use of a low cost computer greatly simplifies hardware and software design, and makes duplication of the instrument very simple and inexpensive.

Waechter, D.A.; Brake, R.J.; Vasilik, D.G.; Erkkila, B.H.

1983-01-01

380

ESTIMATING IMPURITIES IN SURPLUS PLUTONIUM FOR DISPOSITION  

SciTech Connect

The United States holds at least 61.5 metric tons (MT) of plutonium that is permanently excess to use in nuclear weapons programs, including 47.2 MT of weapons-grade plutonium. Surplus inventories will be stored safely by the Department of Energy (DOE) and then transferred to facilities that will prepare the plutonium for permanent disposition. The Savannah River National Laboratory (SRNL) operates a Feed Characterization program for the Office of Fissile Materials Disposition of the National Nuclear Security Administration and the DOE Office of Environmental Management. Many of the items that require disposition are only partially characterized, and SRNL uses a variety of techniques to predict the isotopic and chemical properties that are important for processing through the Mixed Oxide Fuel Fabrication Facility and alternative disposition paths. Recent advances in laboratory tools, including Prompt Gamma Analysis and Peroxide Fusion treatment, provide data on the existing inventories that will enable disposition without additional, costly sampling and destructive analysis.

Allender, J.; Moore, E.

2013-07-17

381

Disposition of plutonium in deep boreholes  

SciTech Connect

Substantial inventories of excess plutonium are expected to result from dismantlement of U.S. and Russian nuclear weapons. Disposition of this material should be a high priority in both countries. A variety of disposition options are under consideration. One option is to place the plutonium either directly or in an immobilized form at the bottom of a deep borehole that is then sealed. Deep-borehole disposition involves placing plutonium several kilometers deep into old, stable, rock formations that have negligible free water present. Containment assurance is based on the presence of ancient groundwater indicating lack of migration and communication with the biosphere. Recovery would be extremely difficult (costly) and impossible to accomplish clandestinely.

Halsey, W.G.; Jardine, L.J.; Walter, C.E.

1995-05-01

382

Chloride removal from plutonium-aluminum alloy dissolver solution prior to purex solvent extraction  

SciTech Connect

The Savannah River Plant (SRP), operated by E. I. du Pont de Nemours Co. for the United States Department of Energy, has successfully recovered plutonium from plutonium-aluminum alloy processed through the F-Canyon Separations facility. The alloy, produced at the Rocky Flats Plant, results from recovery of plutonium residues from spent chloride salts from pyrochemical processing. The alloy, termed scrub alloy'' or Rocky Flats scrub alloy'' (RFSA), contains up to 15 weight percent chloride impurity prior to mercuric ion catalyzed dissolution with fluoride-containing nitric acid. Solutions containing 850 to 3000 {mu}g/mL (parts per million) of chloride result. During subsequent Purex solvent extraction of this solution with 30% tri-n-butyl phosphate in normal paraffin diluent, chloride is rejected to the aqueous waste stream. This stream is eventually evaporated for waste treatment and acid recovery. Chloride concentrations in the product streams, subject to further processing, must be less than 100 {mu}g/mL to prevent excessive corrosion of equipment. This paper describes scrub alloy production at RFP, its dissolution and head end treatment to remove chloride, chloride values in subsequent processing streams including environmental discharges, and the turbidimetric analysis technique. 2 tabs.

Holcomb, H.P.

1990-01-01

383

Plutonium scrap recovery at Savannah River: Past, present, and vision of the future  

SciTech Connect

As a result of the changing requirement, plus environmental and regulatory commitments, SRP now has essentially completed its paradigm shift. SRP has been transformed from primarily a reprocessor of irradiated uranium targets to primarily a reprocessor of non-specification plutonium. This is the mission which will carry SRP into the 21st Century. Accomplishment of the defined goals for the three-pronged RandD program will achieve several objectives: exploit new processes for recovering low-grade scraps; enhance SRP's position to incorporate pyrochemical processes where they are attractive or beneficial to plant scrap recovery; provide SRL/SRP with a capability to develop compatible aqueous pyrochemical processes; identify material compatibility requirements for the incorporation of pyrochemical processes at SRP; promote development and demonstration of improved NDA instrumentation to accurately measure plutonium holdups in solid residues; identify and implement the technology required for reagent preparation and atmospheric quality control; provide a means to compare economic options for emerging new processes; and as a result, identify process steps which will also put SRP in a position to readily adapt to changing plutonium missions.

Gray, L.W.; Gray, J.H.; Blancett, A.L.; Lower, M.W.; Rudisill, T.S.

1988-01-01

384

Disposition of Mixed Waste Organics at the Los Alamos Plutonium Facility  

SciTech Connect

Twenty-six organic solution items totaling 37 L had been stored in the Plutonium Facility vault at the Los Alamos National Laboratory, some for up to 18 years. They were residues from analytical analyses of radioactive solutions. All items had a Resource Conservation and Recovery Act (RCRA) defined hazardous waste combined with special nuclear materials (SNM) and were stored as a mixed waste in a vault room pending disposition. Seventeen items had plutonium concentrations above established discard limits for organics. Due to their age, the containers were not suitable for long-term storage because a container failure would contaminate the vault area and personnel. Therefore, an aqueous-based flowsheet was developed to remove the plutonium so that the items could be discarded. The procedure was a wash with either sodium fluoride and/or potassium hydroxide solution followed by absorbing the discardable organic residues on vermiculite. When this approach did not work permission was obtained to discard the items as a transuranic (TRU) mixed waste without further treatment. The remaining nine solution items were consolidated into two items, repackaged, and stored for future disposition. The overall effort required approximately four months to disposition all the items. This report details the administrative and regulatory requirements that had to be addressed, the results of processing, and the current status of the items.

Ortiz, E.M.; Coriz, F.; Schreiber, S.B.; Balkey, S.; Yarbro, S.L.

1999-02-01

385

Alternating layers of plutonium and lead or indium as surrogate for plutonium  

SciTech Connect

Elemental plutonium (Pu) assumes more crystal structures than other elements, plausibly due to bonding f electrons becoming non-bonding. Complex geometries hamper understanding of the transition in Pu, but calculations predict this transition in a system with simpler geometry: alternating layers either of plutonium and lead or of plutonium and indium. Here the transition occurs via a pairing-up of atoms within Pu layers. Calculations stepping through this pairing-up reveal valuable details of the transition, for example that the transition from bonding to non-bonding proceeds smoothly.

Rudin, Sven Peter [Los Alamos National Laboratory

2009-01-01

386

Decomposition of uranyl nitrate in the silica gel matrix under the action of microwave radiation  

Microsoft Academic Search

Decomposition of aqueous solutions of uranyl nitrate in a matrix of granulated silica gel of KSKG grade under the action of\\u000a microwave radiation (MWR) was studied. Microwave irradiation leads not only to formation of solid decomposition products UO3, UO2(OH)NO3, and their hydrates in pores of KSKG granules, but also to accumulation of gaseous NO\\u000a x\\u000a and H2O. The presence of

S. A. Kulyukhin; A. N. Kamenskaya

2010-01-01

387

Economic discard limits for plutonium recovery  

SciTech Connect

Purpose of the audit was to determine whether the Department used economic discard limits (EDL) for the recovery of weapons-grade plutonium and whether the EDL calculations, if used, were current and accurate. Our review showed that EDL limits had not always been used or were not accurately calculated by some management and operating (M and O) contractors. This occurred because Department management had not updated or ensured implementation of EDL policy and procedures. Partial application of current EDL policy at two contractors prevented the unnecessary disposal of over $5.5 million in plutonium.

Not Available

1988-02-11

388

Continuous process for the production of powdered uranium dioxide from uranyl nitrate  

SciTech Connect

A method is described of producing uranium dioxide powder for the fabrication of nuclear fuel from acidic solutions containing uranyl nitrate, comprising the sequence of steps of: (a) continuously reacting an acidic aqueous solution of uranyl nitrate with ammonium hydroxide added in less than stoichiometric amount for complete uranium precipitation, neutralizing any free acid and precipitating a portion of the uranium content of the solution as ammonium uranate solids; (b) continuously aging the product resulting from reacting the uranyl nitrate of the solution with less than a stoichiometric amount of ammonium hydroxide, including the precipitated ammonium uranate solids while maintaining the solids substantially suspended in the medium of the aqueous solution; (c) thereafter continuously reacting the aged product comprising uranyl nitrate and precipitated ammonium uranate with additional added ammonium hydroxide in amount at least sufficient to complete the precipitation of the uranium of the solution as ammonium uranate solids; and (e) calcining the dewatered ammonium uranate solids in a reducing atmosphere and thereby converting the ammonium uranate solids in a reducing atmosphere and thereby converting the ammonium uranate to uranium dioxide powder.

Divins, L.A.; Runion, H.L.

1987-04-07

389

Solubility of plutonium from rumen contents of cattle grazing on plutonium- contaminated desert vegetation in in vitro bovine gastrointestinal fluids  

Microsoft Academic Search

Rumen contents of cattle grazing on plutonium-contaminated desert ; vegetation at the Nevada Test Site were incubated in simulated bovine ; gastrointestinal fluids to study the alimentary solubility of plutonium. Trials ; were run during November 1973, and during February, May, July and August 1974. ; During the May and July trials, a large increase in plutonium solubility ; accompanied

J. Barth; M. G. White; P. B. Dunaway

1975-01-01

390

Materials identification and surveillance project item evaluation: Items, impure plutonium oxide (ATL27960) and pure plutonium oxide (PEOR3258)  

Microsoft Academic Search

In this report, Los Alamos scientists characterize properties relevant to storage of an impure plutonium oxide (74 mass % plutonium) in accordance with the Department of Energy (DOE) standard DOE-STD-3013-96. This oxide is of interest because it is the first impure plutonium oxide sample to be evaluated and it is similar to other materials that must be stored. Methods used

T. Allen; Q. Appert; C. Davis

1997-01-01

391

High performance ammonium nitrate propellant  

NASA Technical Reports Server (NTRS)

A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

Anderson, F. A. (inventor)

1979-01-01

392

Plutonium dispersal in fires: Summary of what is known  

SciTech Connect

In view of the great public apprehension about plutonium and nuclear weapons we should explore ways to prevent, limit, or mitigate possible plutonium dispersals. This review is primarily a tutorial on what is known about plutonium dispersal in fires. It concludes that in most types of fires involving plutonium the amount released will not be an immediate danger to life. Indeed, in many cases very few personnel will receive more than the lung burden allowed by current regulations for plutonium workers. However, the dangers may be significant in special situations, unusual terrains, certain meteorological conditions, and very high burn temperatures.

Condit, R.H.

1993-07-01

393

Effect of nitrate on microbial perchlorate reduction  

NASA Astrophysics Data System (ADS)

Over the last decade perchlorate has been recognized as an important emerging water contaminant that poses a significant public health threat. Because of its chemical stability, low ionic charge density, and significant water solubility microbial remediation has been identified as the most feasible method for its in situ attenuation. Our previous studies have demonstrated that dissimilatory perchlorate reducing bacteria (DPRB) capable of the respiratory reduction of perchlorate into innocuous chloride are ubiquitous in soil and sedimentary environments. As part of their metabolism these organisms reduce perchlorate to chlorite which is subsequently dismutated into chloride and molecular oxygen. These initial steps are mediated by the perchlorate reductase and chlorite dismutase enzymes respectively. Previously we found that the activity of these organisms is dependent on the presence of molybdenum and is inhibited by the presence of oxygen and to different extents nitrate. However, to date, there is little understanding of the mechanisms involved in the regulation of perchlorate reduction by oxygen and nitrate. As a continuation of our studies into the factors that control DPRB activity we investigated these regulatory mechanisms in more detail as a model organism, Dechloromonas aromatica strain RCB, transitions from aerobic metabolism through nitrate reduction to perchlorate reduction. In series of growth transition studies where both nitrate and perchlorate were present, preference for nitrate to perchlorate was observed regardless of the nitrate to perchlorate ratio. Even when the organism was pre-grown anaerobically in perchlorate, nitrate was reduced prior to perchlorate. Using non-growth washed cell suspension, perchlorate- grown D. aromatica was capable of reducing both perchlorate and nitrate concomitantly suggesting the preferentially utilization of nitrate was not a result of enzyme functionality. To elucidate the mechanism for preferential utilization of nitrate, transcripts of perchlorate reductase and chlorite dismutase were analyzed to determine possible transcriptional regulation from nitrate. During growth transition studies, increase in the level of transcripts necessary for nitrate reduction and perchlorate reduction was observed concomitantly with decrease in the concentration of nitrate and perchlorate respectively suggesting transcriptional regulation was involved in the preferential utilization of nitrate and that nitrate might be a transcriptional inhibitor of perchlorate reduction. Again, using non-growth washed cell suspensions of perchlorate grown D. aromatica, a decrease of transcript level of the perchlorate reductase but not the chlorite dismutase was observed after incubation with nitrate. In conclusion, from physiological and molecular evidence, nitrate negatively regulates transcription of perchlorate reductase thus inhibiting perchlorate reduction. This result is unexpected as it is in contrast to the accepted dogma that microorganisms regulate their metabolisms to utilize electron acceptors in a sequential manner based on thermodynamic optimization which would imply that perchlorate should be used preferentially to nitrate.

Sun, Y.; Coates, J. D.

2007-12-01

394

A strategy for weapons-grade plutonium disposition  

SciTech Connect

A political as well as technical analysis was performed to determine the feasibility of glassification (vitrification) for weapons grade plutonium (WGPu) disposition. The political analysis provided the criteria necessary to compare alternative storage forms. The technical areas of weapon useability and environmental safety were then computationally and experimentally explored and a vitrification implementation strategy postulated. The Monte Carlo Neutron Photon (MCNP) computer code was used to model the effect of blending WGPu with reactor grade Pu (RGPu). A mixture of 30% RGPu and 70% WGPu more than doubled the surface flux from a bare sphere of the mixture which assumedly correlates to a significantly increased predetonation probability. Rare earth diluents were also examined (using MCNP) for their ability to increase the compressed critical mass of the WGPu mixture. The rare earths (notably Eu) were effective in this regard. As Pu-239 has a 24,100 year half life, reactivity control in the long term is an environmental safety issue. Rare earths were investigated as criticality controllers due to their neutron absorption capabilities and insolubility in aqueous environments. Thorium (a Pu surrogate) and the rare earths Eu, Gd, and Sm were added to two standard frits (ARM-1 and SRL-165) and formed into glass. Aqueous leach tests were performed (using MCC-1P guidelines) to measure rare earth leaching and determine the added elements` effects on glass durability. Europium was much more leach resistant than boron in the glasses tested. The elements had no negative effect on the environmental durability of the glasses tested at 90 C and minimal effect at room temperature. No fission product releases were detected in the ARM-1 compositions (which contained numerous simulated fission products).

Sylvester, K.W.B. [Iowa State Univ., Ames, IA (United States)

1994-09-01

395

Dissolution of Plutonium Metal Using a HAN Process  

SciTech Connect

Thermal stability tests were conducted with a nitric acid (HNO3)/hydroxylammonium nitrate (HAN)/potassium fluoride (KF) solution. The solution has great potential for use in plutonium dissolution because of the small quantity of hydrogen and other offgases produced. Tests were carried out in a Reactive Systems Screening Tool (RSST). The RSST is a calorimeter equipped with temperature and pressure probes as well as a heater that can heat a liquid sample at a programmed rate. In most cases, the calorimeter was pressurized with nitrogen to reduce evaporation of the liquid sample during heating. For the proposed solution, an autocatalytic reaction occurred between 113 and 131 degrees Celsius with 300 psig or 50 psig nitrogen inside the RSST vapor space. At ambient pressure, the solution boiled at about 110 degrees Celsius. After extensive boiling, the concentrations of HNO3 and HAN increased and the autocatalytic reaction occurred. Tests were also conducted with 1000 ppm Fe present in the solution. The range of the autocatalytic reaction initiation temperature was reduced to 105-120.5 degrees Celsius. With iron at ambient pressure, boiling still occurred above 100 degrees Celsius prior to the autocatalytic reaction, which occurred at 108-109 degrees Celsius. These results demonstrated the stability of the proposed HAN flowsheet, for which the planned dissolving temperature is 50-60 degrees Celsius. Additional tests were carried out with more concentrated solutions to further characterize the autocatalytic reaction initiation temperature. Increasing the nitric acid concentration to 3M decreased the reaction initiation temperature to 102-103 degrees Celsius. Increasing the HAN concentration increased the temperature rise of the reaction from 10-30 degrees Celsius to greater than 40 degrees Celsius. Increasing both reactants-to 3M nitric acid and 0.9M HAN-yielded a reaction initiation temperature of 91 degrees Celsius (with or without iron), the lowest observed in this study. This study was the first part of a larger flowsheet development / demonstration program for the plutonium metal dissolving process. The results of the study may be useful for similar flowsheets.

CROWDER, MARKL.

2004-06-30

396

Fast photolysis of carbonyl nitrates from isoprene  

NASA Astrophysics Data System (ADS)

We show that photolysis is, by far, the major atmospheric sink of isoprene-derived carbonyl nitrates. Empirical evidence from published laboratory studies on the absorption cross sections and photolysis rates of ?-nitrooxy ketones suggests that the presence of the nitrate group (i) greatly enhances the absorption cross sections, and (ii) facilitates dissociation to a point that the photolysis quantum yield is close to unity, with O-NO2 dissociation as the likely major channel. On this basis, we provide new recommendations for estimating the cross sections and photolysis rates of carbonyl nitrates. The newly estimated photorates are validated using a chemical box model against measured temporal profiles of carbonyl nitrates in an isoprene oxidation experiment by Paulot et al. (2009). The comparisons for ethanal nitrate and for the sum of methacrolein- and methylvinylketone nitrates strongly supports our assumptions of large cross section enhancements and a near-unit quantum yield for these compounds. These findings have significant atmospheric implications, as carbonyl nitrates constitute an important component of the total organic nitrate pool over vegetated areas: the photorates of key carbonyl nitrates from isoprene are estimated to be typically between ~3 and 20 times higher than their sink due to reaction with OH in relevant atmospheric conditions. Moreover, since the reaction is expected to release NO2, photolysis is especially effective in depleting the total organic nitrate pool.

Müller, Jean-Francois; Peeters, Jozef; Stavrakou, Trisevgeni

2014-05-01

397

Nitrate deposition and impact of Adirondack streams  

SciTech Connect

Acidic deposition has a great impact on water chemistry and fish populations in the Adirondack region. Although the Clean Air Act Amendments of 1990 have resulted in some reductions of sulfur deposition, nitrate deposition has not yet been well controlled, and continues to impact aquatic resources. As part of the USEPA funded Episodic Response Project, four Adirondack headwater streams were intensively monitored over an 18 month period. Atmospheric deposition was also monitored at a centrally located station. The quantity of nitrate being deposited on the study watersheds was calculated based on monthly net deposition data, which ranged from 0.6 kg/ha/month to 3.6 kg/ha/month. These data were then compared to the monthly export of nitrate from the watershed in these streams. Nitrate concentrations were highest in the stream water during the spring snowmelt period prior to the time when forest vegetation actively utilizes nitrate. On an annual basis, the amount of nitrate that left the watershed via stream water was approximately equal to the amount that fell as nitrate deposition. These data are important in documenting the impact that nitrate has in acidifying Adirondack streams during the spring, which coincides with brook trout hatching. Control programs for nitrous oxide emissions are presently aimed at reducing ozone levels during the May--September period. These emissions control programs need to be expanded to also reduce nitrate deposition in the sensitive Adirondack region during the water and spring periods when nitrate deposition has its greatest impact on aquatic resources.

Simonin, H.A. [New York State Dept. of Environmental Conservation, Rome, NY (United States). Rome Field Station; Kretser, W. [New York State Dept. of Environmental Conservation, Ray Brook, NY (United States). Adirondack Lakes Survey Corp.

1995-12-31

398

Weapons-grade plutonium dispositioning. Volume 2: Comparison of plutonium disposition options  

SciTech Connect

The Secretary of Energy requested the National Academy of Sciences (NAS) Committee on International Security and Arms Control to evaluate disposition options for weapons-grade plutonium. The Idaho National Engineering Laboratory (INEL) offered to assist the NAS in this evaluation by investigating the technical aspects of the disposition options and their capability for achieving plutonium annihilation levels greater than 90%. This report was prepared for the NAS to document the gathered information and results from the requested option evaluations. Evaluations were performed for 12 plutonium disposition options involving five reactor and one accelerator-based systems. Each option was evaluated in four technical areas: (1) fuel status, (2) reactor or accelerator-based system status, (3) waste-processing status, and (4) waste disposal status. Based on these evaluations, each concept was rated on its operational capability and time to deployment. A third rating category of option costs could not be performed because of the unavailability of adequate information from the concept sponsors. The four options achieving the highest rating, in alphabetical order, are the Advanced Light Water Reactor with plutonium-based ternary fuel, the Advanced Liquid Metal Reactor with plutonium-based fuel, the Advanced Liquid Metal Reactor with uranium-plutonium-based fuel, and the Modular High Temperature Gas-Cooled Reactor with plutonium-based fuel. Of these four options, the Advanced Light Water Reactor and the Modular High Temperature Gas-Cooled Reactor do not propose reprocessing of their irradiated fuel. Time constraints and lack of detailed information did not allow for any further ratings among these four options. The INEL recommends these four options be investigated further to determine the optimum reactor design for plutonium disposition.

Brownson, D.A.; Hanson, D.J.; Blackman, H.S. [and others

1993-06-01

399

Fifty years of plutonium exposure to the Mahattan Project plutonium workers: An update  

Microsoft Academic Search

Twenty-six white male workers who did the original plutonium research and development work at Los Alamos have been examined periodically over the past 50 y to identify possible health effects from internal plutonium depositions. Their effective doses range from 0.1 to 7.2 Sv with a median value of 1.25 Sv. As of the end of 1994, 7 individuals have died

George L. Voelz; James N. P. Lawrence; Emily R. Johnson

1997-01-01

400

Plutonium Immobilization Can Loading Equipment Review  

SciTech Connect

This report lists the operations required to complete the Can Loading steps on the Pu Immobilization Plant Flow Sheets and evaluates the equipment options to complete each operation. This report recommends the most appropriate equipment to support Plutonium Immobilization Can Loading operations.

Kriikku, E. [Westinghouse Savannah River Company, AIKEN, SC (United States); Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.

1998-05-01

401

233-S plutonium concentration facility hazards assessment  

SciTech Connect

This document establishes the technical basis in support of Emergency Planning activities for the 233-S Plutonium Concentration Facility on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE ORDER 5500.3A. Through this document, the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated.

Broz, R.E.

1994-12-19

402

Predicted transport properties of liquid plutonium  

Microsoft Academic Search

The fluid-phase transport properties, diffusivity and viscosity, are calculated by equilibrium and nonequilibrium techniques for plutonium, whose interatomic interactions are described by the modified embedded-atom method. The transport coefficients are evaluated at zero pressure, for temperatures between 950 K and 1300 K. We find the calculated viscosity to be noticeably higher than experiment, while the structure of liquid Pu appears

F. J. Cherne; M. I. Baskes; B. L. Holian

2003-01-01

403

Plutonium isotope ratio variations in North America  

SciTech Connect

Historically, approximately 12,000 TBq of plutonium was distributed throughout the global biosphere by thermo nuclear weapons testing. The resultant global plutonium fallout is a complex mixture whose {sup 240}Pu/{sup 239}Pu atom ratio is a function of the design and yield of the devices tested. The average {sup 240}Pu/{sup 239}Pu atom ratio in global fallout is 0.176 + 014. However, the {sup 240}Pu/{sup 239}Pu atom ratio at any location may differ significantly from 0.176. Plutonium has also been released by discharges and accidents associated with the commercial and weapons related nuclear industries. At many locations contributions from this plutonium significantly alters the {sup 240}Pu/{sup 239}Pu atom ratios from those observed in global fallout. We have measured the {sup 240}Pu/{sup 239}Pu atom ratios in environmental samples collected from many locations in North America. This presentation will summarize the analytical results from these measurements. Special emphasis will be placed on interpretation of the significance of the {sup 240}Pu/{sup 239}Pu atom ratios measured in environmental samples collected in the Arctic and in the western portions of the United States.

Steiner, Robert E [Los Alamos National Laboratory; La Mont, Stephen P [Los Alamos National Laboratory; Eisele, William F [Los Alamos National Laboratory; Fresquez, Philip R [Los Alamos National Laboratory; Mc Naughton, Michael [Los Alamos National Laboratory; Whicker, Jeffrey J [Los Alamos National Laboratory

2010-12-14

404

Proliferation Resistance Attributes of Advanced Plutonium Processing  

Microsoft Academic Search

To obtain public acceptance for future use of Pu, new concepts must overcome the present concerns about environmental compliance as well as con- cerns about misusing plutonium of the civil nuclear fuel cycle for nuclear explosives e.g. by terrorists. In future the preferable remedy is the multi-recycling of all transuranium elements in fast neutron reac- tors. In such a partitioning

L. Koch

405

NNSS Soils Monitoring: Plutonium Valley (CAU366)  

SciTech Connect

The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA), Nevada Site Office (NSO), Environmental Restoration Soils Activity has authorized the Desert Research Institute (DRI) to conduct field assessments of potential sediment transport of contaminated soil from Corrective Action Unit (CAU) 366, Area 11 Plutonium Valley Dispersion Sites Contamination Area (CA) during precipitation runoff events.

Miller, Julianne J.; Mizell, Steve A.; Nikolich, George; Campbell, Scott

2012-02-01

406

High temperature vapor pressure of pure plutonium  

Microsoft Academic Search

High temperature vapor pressure measurements have been made on pure plutonium metal by the Knudsen effusion technique. The reported experimental results extend into the transition region between molecular and viscous or hydrodynamic flow. Under the conditions used, linearity was observed up to temperatures in excess of 2200 K where pressures approaching 100 Pa were measured. The results over the temperature

M. H. Bradbury; R. W. Ohse

1979-01-01

407

Preparation of Plutonium Hexafluoride. Recovery of Plutonium from Waste Dross; PREPARATION DE L'HEXAFLUORURE DE PLUTONIUM. RECUPERATION DU PLUTONIUM DES SCORIES D'ELABORATION  

Microsoft Academic Search

The influence of various physical factors on the rate of fluorination of ; solid plutonium tetrafluoride by fluorine was studied. In a horizontal oven with ; a circulation for pure fluorine at atmospheric pressure and 520#DEC, at a ; fluorine rate of 9 liters\\/hour, it is possible to transform 3 gm of tetrafluoride ; to hexafluoride with about 100% transformation

Gendre

1962-01-01

408

Analysis of femtogram-sized plutonium samples  

SciTech Connect

This report describes a study to determine how well isotopic ratios can be measured for very small samples of plutonium. Resin beads were used to simulate particles; for samples ranging from 5--16 fg, collection efficiencies (ions collected per atom loaded) of 4--9% were obtained. Isotopic ratios with 4% precision and accuracy (240/239) were obtained.

Smith, D.H.; McKown, H.S.; Bostick, D.T.; Coleman, R.M.; Duckworth, D.C.; McPherson, R.L.

1994-01-01

409

PLUTONIUM SPECIATION, SOLUBILIZATION, AND MIGRATION IN SOILS  

EPA Science Inventory

The DOE is currently conducting cleanup activities at its nuclear weapons development sites, many of which have accumulated plutonium (Pu) in soils for 50 years. There is scientific uncertainty about the levels of risk to human health posed by this accumulation and whether Pu is ...

410

Plutonium Immobilization Can Loading Preliminary Specifications  

SciTech Connect

This report discusses the Plutonium Immobilization can loading preliminary equipment specifications and includes a process block diagram, process description, equipment list, preliminary equipment specifications, plan and elevation sketches, and some commercial catalogs. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.

Kriikku, E.

1998-11-25

411

Electrochemically Modulated Separation for Plutonium Safeguards  

SciTech Connect

Accurate and timely analysis of plutonium in spent nuclear fuel is critical in nuclear safeguards for detection of both protracted and rapid plutonium diversions. Gamma spectroscopy is a viable method for accurate and timely measurements of plutonium provided that the plutonium is well separated from the interfering fission and activation products present in spent nuclear fuel. Electrochemically modulated separation (EMS) is a method that has been used successfully to isolate picogram amounts of Pu from nitric acid matrices. With EMS, Pu adsorption may be turned "on" and "off" depending on the applied voltage, allowing for collection and stripping of Pu without the addition of chemical reagents. In this work, we have scaled up the EMS process to isolate microgram quantities of Pu from matrices encountered in spent nuclear fuel during reprocessing. Several challenges have been addressed including surface area limitations, radiolysis effects, electrochemical cell performance stability, and chemical interferences. After these challenges were resolved, 6 µg Pu was deposited in the electrochemical cell with approximately an 800-fold reduction of fission and activation product levels from a spent nuclear fuel sample. Modeling showed that these levels of Pu collection and interference reduction may not be sufficient for Pu detection by gamma spectroscopy. The main remaining challenges are to achieve a more complete Pu isolation and to deposit larger quantities of Pu for successful gamma analysis of Pu. If gamma analyses of Pu are successful, EMS will allow for accurate and timely on-site analysis for enhanced Pu safeguards.

Pratt, Sandra H.; Breshears, Andrew T.; Arrigo, Leah M.; Schwantes, Jon M.; Duckworth, Douglas C.

2013-12-31

412

Importance of poly(ethylene glycol) conformation for the synthesis of silver nanoparticles in aqueous solution  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the formation of silver nanoparticles (NPs) using silver nitrate in a poly(ethylene glycol) (PEG) aqueous solution, which acts as both a reducing and stabilizing agent, the PEG chain structure was found to play a significant role. Even though PEG 100 (100 kg/mol) has limited reducing sites of hyd...

413

Anion influence in lead removal from aqueous solution by deposition onto a vitreous carbon electrode  

Microsoft Academic Search

We investigated the electrolytic removal of Pb(II) from aqueous solutions containing different electrolytes (nitrate, chloride or sulfate), by electrolysis onto reticulated vitreous carbon electrode (RVC). The efficiency of the electrolytic process of lead removal was found to be a function of electrolyte composition. The chloride containing electrolyte, provided the highest efficiency of lead removal, while removing Pb(II) from the sulfate

G. Carreño; E. Sosa; I. González; C. Ponce-de-León; N. Batina; M. T. Oropeza

1999-01-01

414

Nitrate uptake improvement by modified activated carbons developed from two species of pine cones.  

PubMed

Activated carbons from two species of pine cones (Pinus canariensis and Cupressus sempervirens) were prepared by phosphoric acid activation and tested for the removal of nitrate ions from aqueous solution. To investigate the feasibility of improving their nitrate adsorption capacity, two different post-treatments—a thermal treatment and a treatment with saturated urea solution—were also applied to the prepared activated carbons. Comparison of the treated and untreated activated carbons showed that both post-treatments improved the nitrate adsorption performance more than twice. The maximum adsorption capacity, as evaluated from determination of the adsorption isotherms for the P. canariensis based carbons, and their proper representation by the Langmuir model, demonstrated that the post-treatment with the urea solution led to activated carbons with increased nitrate removal effectiveness, even superior to other reported results. Enhancements in their adsorption capacity could be mainly ascribed to higher contents of nitrogen and basic functional groups, whereas porous structure of the activated carbons did not seem to play a key role in the nitrate uptake. PMID:25460695

Nunell, G V; Fernandez, M E; Bonelli, P R; Cukierman, A L

2015-02-15

415

In search of plutonium: A nonproliferation journey  

NASA Astrophysics Data System (ADS)

In February 1992, I landed in the formerly secret city of Sarov, the Russian Los Alamos, followed a few days later by a visit to Snezhinsk, their Livermore. The briefings we received of the Russian nuclear weapons program and tours of their plutonium, reactor, explosives, and laser facilities were mind boggling considering the Soviet Union was dissolved only two months earlier. This visit began a 17-year, 41 journey relationship with the Russian nuclear complex dedicated to working with them in partnership to protect and safeguard their weapons and fissile materials, while addressing the plight of their scientists and engineers. In the process, we solved a forty-year disagreement about the plutonium-gallium phase diagram and began a series of fundamental plutonium science workshops that are now in their tenth year. At the Yonbyon reprocessing facility in January 2004, my North Korean hosts had hoped to convince me that they have a nuclear deterrent. When I expressed skepticism, they asked if I wanted to see their ``product.'' I asked if they meant the plutonium; they replied, ``Well, yes.'' Thus, I wound up holding 200 grams of North Korean plutonium (in a sealed glass jar) to make sure it was heavy and warm. So began the first of my six journeys to North Korea to provide technical input to the continuing North Korean nuclear puzzle. In Trombay and Kalpakkam a few years later I visited the Indian nuclear research centers to try to understand how India's ambitious plans for nuclear power expansion can be accomplished safely and securely. I will describe these and other attempts to deal with the nonproliferation legacy of the cold war and the new challenges ahead. )

Hecker, Siegfried

2010-02-01

416

Effects of precursor chemistry and thermal treatment conditions on obtaining phase pure bismuth ferrite from aqueous gel precursors  

Microsoft Academic Search

Phase pure BiFeO3 powders are synthesized by an entirely aqueous solution–gel route, starting from water soluble Fe(III) nitrate or citrate, and Bi(III) citrate as precursors. In order to obtain stable solutions, which transform to homogeneous gels upon drying, the pH is adjusted to 7 and a citric acid content equimolar to the metal ions is selected.The presence of nitrate strongly

A. Hardy; S. Gielis; H. Van den Rul; J. D’Haen; M. K. Van Bael; J. Mullens

2009-01-01

417

Binary lanthanide(III)/nitrate and ternary lanthanide(III)/nitrate/chloride complexes in an ionic liquid containing water: optical absorption and luminescence studies.  

PubMed

The formation of binary Ln(iii)/nitrate and ternary Ln(iii)/nitrate/chloride complexes in a water-saturated ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide (denoted BumimTf(2)N), was investigated by absorption spectrophotometry and luminescence spectroscopy. Four successive binary complexes, Nd(NO(3))(2+), Nd(NO(3))(2)(+), Nd(NO(3))(3), and Nd(NO(3))(4)(-), were identified, and their stability constants in water-saturated BumimTf(2)N are several orders of magnitude higher than those in aqueous solutions, but much lower than those observed in dry BumimTf(2)N. The complexation of lanthanides with nitrate in wet BumimTf(2)N proceeds via the replacement of water molecules by bidentate nitrate anions from the inner solvation spheres of Ln(3+) cations. In the absence of nitrate, the precipitation of Ln(iii)/chloride complex(es) occurs at low ratios of C(Cl)/C(Ln) (<6) in BumimTf(2)N, which precludes the determination of stability constants of binary Ln(iii)/chloride complexes by spectrophotometry or luminescence spectroscopy. However, using a competition approach, the formation of two ternary complexes, Ln(NO(3))(3)Cl(2)(2-) and Ln(NO(3))(2)Cl(4)(3-), has been observed and their stability constants in wet BumimTf(2)N were determined. Data indicate that both nitrate and chloride are stronger ligands than water for lanthanides in BumimTf(2)N. PMID:25567210

Ansari, Seraj A; Liu, Lisheng; Rao, Linfeng

2015-02-14

418

Actinide removal from aqueous solution with activated magnetite  

SciTech Connect

An actinide aqueous waste treatment process using activated magnetite has been developed at Rocky Flats. The use and effectiveness of various magnetites in lowering actinide concentrations in aqueous solution are described. Experiments indicate that magnetite particle size and pretreatment (activation of the magnetite surface with hydroxyl ions greatly influence the effective use of magnetite as an actinide adsorbent. With respect to actinide removal, Ba(OH)/sub 2/-activated magnetite was more effective over a broader pH range than was NaOH-activated magnetite. About 50% less Ba(OH)/sub 2/-activated magnetite was required to lower plutonium concentration from 10/sup -4/ to 10/sup -8/ g/l. 7 refs., 8 tabs.

Kochen, R.L.; Thomas, R.L. (ed.)

1987-08-10

419

New organic nitrate-containing benzyloxy isonipecotanilide derivatives with vasodilatory and anti-platelet activity.  

PubMed

A number of new nitric oxide (NO)-precursors were synthesized by grafting nitrate-containing moieties on the structures of the benzyloxy isonipecotanilide derivatives 1 and 2 already reported as moderately potent antiplatelet agents. Various nitrooxy (ONO2)-alkyl side chains were covalently linked to the piperidine nitrogen of the parent compounds through carbamate and amide linkage, and the synthesis of a benzyl nitrate analog (15) of compound 1 was also achieved. The in vitro vasodilatory activities, as well as platelet anti-aggregatory effects, of the newly synthesized organic nitrates were assessed. The (ONO2)methyl carbamate-based derivative 5a and the benzyl nitrate analog 15, which on the other hand retain activity as inhibitors of ADP-induced platelet aggregation, exhibited strong NO-mediated vasodilatory effects on pre-contracted rat aorta strips, with EC50 values in the low nanomolar range (13 and 29nM, respectively). Experiments carried out with the selectively inhibited soluble guanylate cyclase (sGC), which is the key enzyme of the NO-mediated pathway leading to vascular smooth muscle relaxation, confirmed the involvement of NO in the observed vasodilation. The nitrate derivatives proved to be stable in acidic aqueous solution and at pH 7.4. In human serum, unlike 5a, which showed not to undergo enzyme-catalyzed decomposition, the other tested (ONO2)-alkyl carbamate-based compounds (5b and 5e) and benzyl nitrate 15 underwent a faster degradation. However, their decomposition rates in serum were quite slow (t½>2.6h), which suggests that nitrate moiety is poorly metabolized in blood plasma and that much of the in vitro anti-platelet activity has to be attributed to the intact (ONO2)-containing molecules. PMID:25769522

de Candia, Modesto; Marini, Elisabetta; Zaetta, Giorgia; Cellamare, Saverio; Di Stilo, Antonella; Altomare, Cosimo D

2015-05-25

420

Aqueous extracts of microalgae exhibit antioxidant and anticancer activities  

PubMed Central

Objective To investigate the antioxidant and anticancer activities of aqueous extracts of nine microalgal species. Methods Variable percentages of major secondary metabolites (total phenolic content, terpenoids and alkaloids) as well as phycobiliprotein pigments (phycocyanin, allophycocyanin and phycoerythrin) in the aqueous algal extracts were recorded. Antioxidant activity of the algal extracts was performed using 2, 2 diphenyl-1-picrylhydrazyl (DPPH) test and 2,2?- azino-bis (ethylbenzthiazoline-6-sulfonic acid (ABTS.+) radical cation assay. Anticancer efficiency of the algal water extracts was investigated against Ehrlich Ascites Carcinoma cell (EACC) and Human hepatocellular cancer cell line (HepG2). Results Antioxidant activity of the algal extracts was performed using DPPH test and ABTS.+ radical cation assays which revealed 30.1-72.4% and 32.0-75.9% respectively. Anticancer efficiency of the algal water extracts was investigated against Ehrlich Ascites Carcinoma Cell (EACC) and Human Hepatocellular cancer cell line (HepG2) with an activity ranged 87.25% and 89.4% respectively. Culturing the promising cyanobacteria species; Nostoc muscorum and Oscillatoria sp. under nitrogen stress conditions (increasing and decreasing nitrate content of the normal BG11 medium, 1.5 g/L), increased nitrate concentration (3, 6 and 9 g/L) led to a remarkable increase in phycobilin pigments followed by an increase in both antioxidant and anticancer activities in both cyanobacterial species. While the decreased nitrate concentration (0.75, 0.37 and 0.0 g/L) induced an obvious decrease in phycobilin pigments with complete absence of allophycocyanin in case of Oscillatoria sp. Conclusions Nitrogen starvation (0.00 g/L nitrate) induced an increase and comparable antioxidant and anticancer activities to those cultured in the highest nitrate content. PMID:23569980

Shanab, Sanaa MM; Mostafa, Soha SM; Shalaby, Emad A; Mahmoud, Ghada I

2012-01-01

421

Pollution of drinking water with nitrate  

Microsoft Academic Search

The main sources of nitrate in man are food and drinking water. The legislature in West Germany intends to lower the permitted level of nitrate in drinking water from the present 90 mg\\/l to 50 mg\\/l in 1982. The European Community has issued a directive that recommends a level of only 25 mg\\/l, and for babies 10 mg\\/l nitrate should

B. Cabel; R. Kozicki; U. Lahl; A. Podbielshi; B. Stachel; S. Struss

1982-01-01

422

Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.  

ERIC Educational Resources Information Center

Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

Bretherick, Leslie

1989-01-01

423

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY...

2010-10-01

424

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2011 CFR

...5 compatibility group D. (f) No mixture containing ammonium nitrate and any ingredient which would accelerate the decomposition of ammonium nitrate under conditions incident to transportation may be transported by vessel. [Amdt. 176-30,...

2011-10-01

425

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2014 CFR

...5 compatibility group D. (f) No mixture containing ammonium nitrate and any ingredient which would accelerate the decomposition of ammonium nitrate under conditions incident to transportation may be transported by vessel. [Amdt. 176-30,...

2014-10-01

426

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2012 CFR

...5 compatibility group D. (f) No mixture containing ammonium nitrate and any ingredient which would accelerate the decomposition of ammonium nitrate under conditions incident to transportation may be transported by vessel. [Amdt. 176-30,...

2012-10-01

427

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.  

Code of Federal Regulations, 2013 CFR

...5 compatibility group D. (f) No mixture containing ammonium nitrate and any ingredient which would accelerate the decomposition of ammonium nitrate under conditions incident to transportation may be transported by vessel. [Amdt. 176-30,...

2013-10-01

428

Plutonium, Mineralogy and Radiation Effects  

NASA Astrophysics Data System (ADS)

During the past fifty years, more than 1,800 metric tonnes of Pu and substantial quantities of other "minor" actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranic elements can be a source of energy in fission reactions (e.g., 239Pu), a source of fissile material for nuclear weapons (e.g., 239Pu and 237Np), or are of environmental concern because of their long half- lives and radiotoxicity (e.g., 239Pu, t1/2 = 24,100 years, and 237Np, t1/2 = 2.1 million years). There are two basic strategies for the disposition of these elements: 1.) to "burn" or transmute the actinides using nuclear reactors or accelerators; 2.) to "sequester" the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, such as zircon or isometric pyrochlore, A2B2O7 (A = rare earths; B = Ti, Zr, Sn, Hf; Fd3m; Z=8), for the immobilization of actinides, particularly plutonium. One of the principal concerns has been the accumulation of structural damage caused by alpha-decay events, particularly from the recoil nucleus. Systematic ion beam irradiation studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high fluences of alpha-decay event damage. Some compositions, Gd2Ti2O7, are amorphized at relatively low doses (0.2 displacements per atom, dpa, at room temperature), while other compositions, Gd2Zr2O7, do not amorphize (even at doses of > 40 dpa at 25K), but instead disorder to a defect fluorite structure. By changing the composition of the A-site (e.g., substitution of different rare earth elements), the temperature above which the pyrochlore composition can no longer be amorphized, Tc, varies by >600 K (e.g., Lu2Ti2O7: Tc = 480 K; Gd2Ti2O7: Tc = 1120 K). The variation in response to irradiation as a function of composition can be used to model the long-term accumulation of radiation damage as a function of the thermal period of a geologic repository. As an example, with a 10 wt.% loading of 239Pu, Gd2Ti2O7 will become amorphous in less than 1,000 years, while Gd2Zr2O7 will persist as a disordered defect fluorite structure. Thus, the radiation stability of different pyrochlores is closely related to the structural distortions that occur for specific pyrochlore compositions and the electronic structure of the B-site cation. This understanding provides the basis for designing materials for the safe, long-term immobilization and sequestration of actinides.

Ewing, R. C.

2006-05-01

429

Fast photolysis of carbonyl nitrates from isoprene  

NASA Astrophysics Data System (ADS)

Photolysis is shown to be a major sink for isoprene-derived carbonyl nitrates, which constitute an important component of the total organic nitrate pool over vegetated areas. Empirical evidence from published laboratory studies on the absorption cross sections and photolysis rates of ?-nitrooxy ketones suggests that the presence of the nitrate group (i) greatly enhances the absorption cross sections and (ii) facilitates dissociation to a point that the photolysis quantum yield is close to unity, with O-NO2 dissociation as a likely major channel. On this basis, we provide new recommendations for estimating the cross sections and photolysis rates of carbonyl nitrates. The newly estimated photo rates are validated using a chemical box model against measured temporal profiles of carbonyl nitrates in an isoprene oxidation experiment by Paulot et al. (2009). The comparisons for ethanal nitrate and for the sum of methacrolein- and methyl vinyl ketone nitrates strongly supports our assumptions of large cross-section enhancements and a near-unit quantum yield for these compounds. These findings have significant atmospheric implications: the photorates of key carbonyl nitrates from isoprene are estimated to be typically between ~ 3 and 20 times higher than their sink due to reaction with OH in relevant atmospheric conditions. Moreover, since the reaction is expected to release NO2, photolysis is especially effective in depleting the total organic nitrate pool.

Müller, J.-F.; Peeters, J.; Stavrakou, T.

2014-03-01

430

Photochemistry of Nitrate Adsorbed on Mineral Dust  

NASA Astrophysics Data System (ADS)

Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

Gankanda, A.; Grassian, V. H.

2013-12-01

431

A Note on the Reaction of Hydrogen and Plutonium  

SciTech Connect

Plutonium hydride has many practical and experimental purposes. The reaction of plutonium and hydrogen has interesting characteristics, which will be explored in the following analysis. Plutonium is a radioactive actinide metal that emits alpha particles. When plutonium metal is exposed to air, the plutonium oxides and hydrides, and the volume increases. PuH{sub 2} and Pu{sub 2}O{sub 3} are the products. Hydrogen is a catalyst for plutonium's corrosion in air. The reaction can take place at room temperature because it is fairly insensitive to temperature. Plutonium hydride, or PuH{sub 2}, is black and metallic. After PuH{sub 2} is formed, it quickly flakes off and burns. The reaction of hydrogen and plutonium is described as pyrophoric because the product will spontaneously ignite when oxygen is present. This tendency must be considered in the storage of metal plutonium. The reaction is characterized as reversible and nonstoichiometric. The reaction goes as such: Pu + H{sub 2} {yields} PuH{sub 2}. When PuH{sub 2} is formed, the hydrogen/plutonium ratio is between 2 and 2.75 (approximately). As more hydrogen is added to the system, the ratio increases. When the ratio exceeds 2.75, PuH{sub 3} begins to form along with PuH{sub 2}. Once the ratio surpasses 2.9, only PuH{sub 3} remains. The volume of the plutonium sample increases because of the added hydrogen and the change in crystal structure which the sample undergoes. As more hydrogen is added to a system of metal plutonium, the crystal structure evolves. Plutonium has a crystal structure classified as monoclinic. A monoclinic crystal structure appears to be a rectangular prism. When plutonium reacts with hydrogen, the product PuH{sub 2}, becomes a fluorite structure. It can also be described as a face centered cubic structure. PuH{sub 3} forms a hexagonal crystal structure. As plutonium evolves from metal plutonium to plutonium hydride to plutonium trihydride, the crystal structure evolves from monoclinic to fluorite to hexagonal. This change in crystal structure as a result of adding hydrogen is a shared characteristic with other actinide elements. Americium is isostructural with plutonium because they both form cubic dihyrides and hexagonal trihydrides. Reacting hydrogen with plutonium has the practical application of separating plutonium from other materials that don't react as well with hydrogen. When plutonium is placed in a chamber where there is very little oxygen, it can react with hydrogen without igniting. The hydrogen plutonium reaction can then be reversed, thus regaining the separated plutonium. Another application of this reaction is that it can be used to predict how plutonium reacts with other substances. Deuterium and tritium are two isotopes of hydrogen that are of interest. They are known to react likewise to hydrogen because they have similar properties. The reaction of plutonium and isotopes of hydrogen can prove to be very informative.

Noone, Bailey C [Los Alamos National Laboratory

2012-08-15

432

Free amino acids, nitrate, and nitrate reductase in nitrogen fixation by soybean nodules  

E-print Network

FREE AMINO ACIDS, NITRATE, AND NITRATE REDUCTASE IN NITROGEN FIXATION BY SOYBEAN NODULES A Thesis by PAUL CLAYTON MADTES, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1978 Major Subject: Biophysics FREE AMINO ACIDS, NITRATE, AND NITRATE REDUCTASE IN NITROGEN FIXATION BY SOYBEAN NPDULES A Thesis by PAUL CLAYTON MADTES, JR. Approved as to style and content by: g jap (Chairman...

Madtes, Paul Clayton

1978-01-01

433

PLUTONIUM CONTAMINATION VALENCE STATE DETERMINATION USING X-RAY ABSORPTION FINE STRUCTURE PERMITS CONCRETE RECYCLE  

SciTech Connect

This paper describes the determination of the speciation of plutonium contamination present on concrete surfaces at the Rocky Flats Environmental Technology Site (RFETS). At RFETS, the plutonium processing facilities have been contaminated during multiple events over their 50 year operating history. Contamination has resulted from plutonium fire smoke, plutonium fire fighting water, milling and lathe operation aerosols, furnace operations vapors and plutonium ''dust'' diffusion.

Ervin, P. F.; Conradson, S. D.

2002-02-25

434

MCNP5 CALCULATIONS REPLICATING ARH-600 NITRATE DATA  

SciTech Connect

This report serves to extend the previous document: 'MCNP Calculations Replicating ARH-600 Data' by replicating the nitrate curves found in ARH-600. This report includes the MCNP models used, the calculated critical dimension for each analyzed parameter set, and the resulting data libraries for use with the CritView code. As with the ARH-600 data, this report is not meant to replace the analysis of the fissile systems by qualified criticality personnel. The M CNP data is presented without accounting for the statistical uncertainty (although this is typically less than 0.001) or bias and, as such, the application of a reasonable safety margin is required. The data that follows pertains to the uranyl nitrate and plutonium nitrate spheres, infinite cylinders, and infinite slabs of varying isotopic composition, reflector thickness, and molarity. Each of the cases was modeled in MCNP (version 5.1.40), using the ENDF/B-VI cross section set. Given a molarity, isotopic composition, and reflector thickness, the fissile concentration and diameter (or thicknesses in the case of the slab geometries) were varied. The diameter for which k-effective equals 1.00 for a given concentration could then be calculated and graphed. These graphs are included in this report. The pages that follow describe the regions modeled, formulas for calculating the various parameters, a list of cross-sections used in the calculations, a description of the automation routine and data, and finally the data output. The data of most interest are the critical dimensions of the various systems analyzed. This is presented graphically, and in table format, in Appendix B. Appendix C provides a text listing of the same data in a format that is compatible with the CritView code. Appendices D and E provide listing of example Template files and MCNP input files (these are discussed further in Section 4). Appendix F is a complete listing of all of the output data (i.e., all of the analyzed dimensions and the resulting k{sub eff} values).

FINFROCK SH

2011-10-25

435

Environmentally Responsible Use of Nanomaterials for the Photocatalytic Reduction of Nitrate in Water  

NASA Astrophysics Data System (ADS)

Nitrate is the most prevalent water pollutant limiting the use of groundwater as a potable water source. The overarching goal of this dissertation was to leverage advances in nanotechnology to improve nitrate photocatalysis and transition treatment to the full-scale. The research objectives were to (1) examine commercial and synthesized photocatalysts, (2) determine the effect of water quality parameters (e.g., pH), (3) conduct responsible engineering by ensuring detection methods were in place for novel materials, and (4) develop a conceptual framework for designing nitrate-specific photocatalysts. The key issues for implementing photocatalysis for nitrate drinking water treatment were efficient nitrate removal at neutral pH and by-product selectivity toward nitrogen gases, rather than by-products that pose a human health concern (e.g., nitrite). Photocatalytic nitrate reduction was found to follow a series of proton-coupled electron transfers. The nitrate reduction rate was limited by the electron-hole recombination rate, and the addition of an electron donor (e.g., formate) was necessary to reduce the recombination rate and achieve efficient nitrate removal. Nano-sized photocatalysts with high surface areas mitigated the negative effects of competing aqueous anions. The key water quality parameter impacting by-product selectivity was pH. For pH < 4, the by-product selectivity was mostly N-gas with some NH4 +, but this shifted to NO2- above pH = 4, which suggests the need for proton localization to move beyond NO2 -. Co-catalysts that form a Schottky barrier, allowing for localization of electrons, were best for nitrate reduction. Silver was optimal in heterogeneous systems because of its ability to improve nitrate reduction activity and N-gas by-product selectivity, and graphene was optimal in two-electrode systems because of its ability to shuttle electrons to the working electrode. "Environmentally responsible use of nanomaterials" is to ensure that detection methods are in place for the nanomaterials tested. While methods exist for the metals and metal oxides examined, there are currently none for carbon nanotubes (CNTs) and graphene. Acknowledging that risk assessment encompasses dose-response and exposure, new analytical methods were developed for extracting and detecting CNTs and graphene in complex organic environmental (e.g., urban air) and biological matrices (e.g. rat lungs).

Doudrick, Kyle

436

Effect of nitrate and incubation conditions on the production of catalase and nitrate reductase by staphylococci  

Microsoft Academic Search

The objective of this work was to study the production of catalase and nitrate reductase by staphylococci in order to understand their role in lipid oxidation during sausage manufacturing. Catalase and nitrate reductase were measured in resting cells and supernatants of staphylococci grown in different conditions. All staphylococci (except S. warneri) synthetized nitrate reductase. In static condition, the synthesis was

R Talon; D Walter; S Chartier; C Barrière; M. C Montel

1999-01-01

437

Rapid colorimetric determination of nitrate in plant tissue by nitration of salicylic acid  

Microsoft Academic Search

An analysis is described for the rapid determination of nitrate?N in plant extracts. The complex formed by nitration of salicylic acid under highly acidic conditions absorbs maximally at 410 nm in basic (pH>12) solutions. Absorbance of the chromophore is directly proportional to the amount of nitrate?N present. Ammonium, nitrite, and chloride ions do not interfere.

D. A. Cataldo; M. Maroon; L. E. Schrader; V. L. Youngs

1975-01-01

438

Challenges with nitrate therapy and nitrate tolerance: prevalence, prevention, and clinical relevance.  

PubMed

Nitrate therapy has been an effective treatment for ischemic heart disease for over 100 years. The anti-ischemic and exercise-promoting benefits of sublingually administered nitrates are well established. Nitroglycerin is indicated for the relief of an established attack of angina and for prophylactic use, but its effects are short lived. In an effort to increase the duration of beneficial effects, long-acting orally administered and topical applications of nitrates have been developed; however, following their continued or frequent daily use, patients soon develop tolerance to these long-acting nitrate preparations. Once tolerance develops, patients begin losing the protective effects of the long-acting nitrate therapy. By providing a nitrate-free interval, or declining nitrate levels at night, one can overcome or reduce the development of tolerance, but cannot provide 24-h anti-anginal and anti-ischemic protection. In addition, patients may be vulnerable to occurrence of rebound angina and myocardial ischemia during periods of absent nitrate levels at night and early hours of the morning, and worsening of exercise capacity prior to the morning dose of the medication. This has been a concern with nitroglycerin patches but not with oral formulations of isosorbide-5 mononitrates, and has not been adequately studied with isosorbide dinitrate. This paper describes problems associated with nitrate tolerance, reviews mechanisms by which nitrate tolerance and loss of efficacy develop, and presents strategies to avoid nitrate tolerance and maintain efficacy when using long-acting nitrate formulations. PMID:24664980

Thadani, Udho

2014-08-01

439

REDUCTION OF NITRATE THROUGH THE USE OF NITRATE REDUCTASE FOR THE SMARTCHEM AUTOANALYZER  

EPA Science Inventory

The standard method for the determination of nitrate in drinking water, USEPA Method 353.2 ¿Determination of Nitrate-Nitrite by Automated Colorimetry,¿ employs cadmium as the reductant for the conversion of nitrate to nitrite. The nitrite is then analyzed colorimetrically by way ...

440

Nitration of Benzo Crown Ethers with Potassium Nitrate in Polyphosphoric Acid  

Microsoft Academic Search

A general method for the nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid has been developed. Mono- and dinitro derivatives of benzo-12-crown-4, benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8 have been prepared. The role of complex formation in the regioselective tendency for the nitration of dibenzo-18-crown-6 has been demonstrated.

A. D. Grebenyuk; S. A. Andreev; I. A. Stempnevskaya; M. G. Levkovich; A. K. Tashmukhamedova

2000-01-01

441

The NreA protein functions as a nitrate receptor in the staphylococcal nitrate regulation system.  

PubMed

Staphylococci are able to use nitrate as an alternative electron acceptor during anaerobic respiration. The regulation of energy metabolism is dependent on the presence of oxygen and nitrate. Under anaerobic conditions, staphylococci employ the nitrate regulatory element (Nre) for transcriptional activation of genes involved in reduction and transport of nitrate and nitrite. Of the three proteins that constitute the Nre system, NreB has been characterized as an oxygen sensor kinase and NreC has been characterized as its cognate response regulator. Here, we present structural and functional data that establish NreA as a new type of nitrate receptor. The structure of NreA with bound nitrate was solved at 2.35Å resolution, revealing a GAF domain fold. Isothermal titration calorimetry experiments showed that NreA binds nitrate with low micromolar affinity (KD=22?M). Two crystal forms for NreA were obtained, with either bound nitrate or iodide. While the binding site is hydrophobic, two helix dipoles and polar interactions contribute to specific binding of the ions. The expression of nitrate reductase (NarGHI) was examined using a narG-lip (lipase) reporter gene assay in vivo. Expression was regulated by the presence of NreA and nitrate. Structure-guided mutations of NreA reduced its nitrate binding affinity and also affected the gene expression, thus providing support for the function of NreA as a nitrate receptor. PMID:24389349

Niemann, Volker; Koch-Singenstreu, Mareike; Neu, Ancilla; Nilkens, Stephanie; Götz, Friedrich; Unden, Gottfried; Stehle, Thilo

2014-04-01

442

PUREX (Plutonium-Uranium Extraction) L-Cell concentrator corrosion evaluation  

SciTech Connect

Problems with solids plugging the piping associated with the E-L7-1 concentrator at the Plutonium-Uranium Extraction (PUREX) Plant were experienced shortly after it was put into use in 1971. The transfer line from the concentrator was first plugged in 1972. The PUREX Plant was shut down shortly thereafter after processing of available feed was finished. The plant was restarted in 1983, and plugging occurred again in early 1985. Both times, the transfer line was cleared by pulsing the fluid. The transfer line was replaced because of plugging in mid-1986 when pulsing failed to remove the plug. The concentrator, which is made of titanium, is used for the final concentration of the plutonium nitrate solution. The solids plugging the transfer line were identified as both the rutile and anatase forms of titanium dioxide. Ultrasonic examinations of titanium equipment in L-Cell showed that the concentrator wall thickness was decreasing as the acid refluxing area of the E-L7-1 tower was approached. The PUREX Plant Systems and Technology then requested the Plutonium Process Support Laboratories (PPSL) to set up and perform experiments to determine the cause(s) and possible corrective actions for the E-L7-1 corrosion. After testing samples of titanium and other metals under controlled conditions identical to E-L7-1 concentrator operation, zirconium was selected for long-term testing as a replacement for the tower section. Two long-term test apparatus were then built and tested on a pilot scale. 9 refs., 13 figs., 5 tabs.

Compton, J. A.; Delegard, C. H.

1990-05-01

443

The effect of x rays, DTPA, and aspirin on the absorption of plutonium from the gastrointestinal tract of rats  

SciTech Connect

To measure the effect of radiation on plutonium transport, rats that were exposed to 250-kVp X rays were given /sup 238/Pu 3 days afterwards by either gavage or injection into a ligated segment of the duodenum. In a second group of experiments, rats were either injected intraduodenally with /sup 238/Pu-DTPA or administered the chelate intravenously and the /sup 238/Pu by gavage. In a third experiment, rats that had been gavaged with 200 or 400 mg/kg/day of aspirin for 2 days were injected intragastrically with /sup 238/Pu nitrate. Results of the first experiment showed a dose-dependent increase in /sup 238/Pu absorption between 800 and 1500 rad of lower-body X irradiation. Intravenous or intraduodenal injections of DTPA caused a marked increase in /sup 238/Pu absorption but resulted in decreased plutonium deposition in the skeleton and liver. Retention of /sup 238/Pu in the skeleton of rats given aspirin was double that of controls, but the effect on plutonium absorption was less marked than that of DTPA.

Sullivan, M.F.; Gorham, L.S.; Miller, B.M.

1983-04-01

444

Nitrate reduction functional genes and nitrate reduction potentials persist in deeper estuarine sediments. Why?  

PubMed

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases. PMID:24728381

Papaspyrou, Sokratis; Smith, Cindy J; Dong, Liang F; Whitby, Corinne; Dumbrell, Alex J; Nedwell, David B

2014-01-01

445

Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. Why?  

PubMed Central

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases. PMID:24728381

Papaspyrou, Sokratis; Smith, Cindy J.; Dong, Liang F.; Whitby, Corinne; Dumbrell, Alex J.; Nedwell, David B.

2014-01-01

446

Speciation in aqueous solutions of nitric acid.  

PubMed

In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approximation (BiMSA), or associative MSA (AMSA), in which the size and the charge of the ions in the chemical pair may differ from those of the free ions. A simultaneous fit of the osmotic coefficient and of the proportion of free ions (obtained from Raman spectroscopy experiments) led to an estimation of the speciation in nitric acid solutions. The result obtained using this procedure was compared with the estimation obtained from the Raman experiments. PMID:23258765

Hlushak, S; Simonin, J P; De Sio, S; Bernard, O; Ruas, A; Pochon, P; Jan, S; Moisy, P

2013-02-28

447

The contributions of nitrate uptake and efflux to isotope fractionation during algal nitrate assimilation  

NASA Astrophysics Data System (ADS)

In order to strengthen environmental application of nitrate N and O isotopes, we measured the N and O isotopic fractionation associated with cellular nitrate uptake and efflux in the nitrate-assimilating marine diatom Thalassiosira weissflogii. We isolated nitrate uptake and efflux from nitrate reduction by growing the cells in the presence of tungsten, which substitutes for molybdenum in assimilatory nitrate reductase, yielding an inactive enzyme. After growth on ammonium and then N starvation, cells were exposed to nitrate. Numerical models fit to the evolution of intracellular nitrate concentration and N and O isotopic composition yielded distinct N isotope effects (15?) for nitrate uptake and nitrate efflux (2.0 ± 0.3‰ and 1.2 ± 0.4‰, respectively). The O isotope effects (18?) for nitrate uptake and nitrate efflux were indistinguishable (2.8 ± 0.6‰), yielding a ratio of O to N isotopic fractionation for uptake of 1.4 ± 0.4 and for efflux of 2.3 ± 0.9. The 15? for nitrate uptake can account for at most 40% of the organism-level N isotope effect (15?org) measured in laboratory studies of T. weissflogii and in the open ocean (typically 5‰ or greater). This observation supports previous evidence that most isotope fractionation during nitrate assimilation is due to intracellular nitrate reduction, with nitrate efflux allowing the signal to be communicated to the environment. An O to N fractionation ratio (18?org:15?org) of ˜1 has been measured for nitrate assimilation in algal cultures and linked to the N and O isotope effects of nitrate reductase. Our results suggest that the ratios of O to N fractionation for both nitrate uptake and efflux may be distinct from a ratio of 1, to a degree that could cause the net 18?org:15?org to rise appreciably above 1 when 15?org is low (e.g., yielding a ratio of 1.1 when 15?org is 5‰). However, field and culture studies have consistently measured nearly equivalent fractionation of N and O isotopes in association with low isotope effects, calling for isotopic studies of nitrate transport by other phytoplankton strains.

Karsh, K. L.; Trull, T. W.; Sigman, D. M.; Thompson, P. A.; Granger, J.

2014-05-01

448

78 FR 32690 - Certain Ammonium Nitrate From Ukraine  

Federal Register 2010, 2011, 2012, 2013, 2014

...Review)] Certain Ammonium Nitrate From Ukraine Determination On the basis of the record...order on certain ammonium nitrate from Ukraine would be likely to lead to continuation...entitled Certain Ammonium Nitrate from Ukraine: Investigation No....

2013-05-31

449

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM NITRATE IN STORAGE. APRIL 18, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

450

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Calcium nitrate fertilizers. 148.227...Certain Materials § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting...

2012-10-01

451

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Calcium nitrate fertilizers. 148.227...Certain Materials § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting...

2011-10-01

452

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Calcium nitrate fertilizers. 148.227...Certain Materials § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting...

2013-10-01

453

46 CFR 148.227 - Calcium nitrate fertilizers.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Calcium nitrate fertilizers. 148.227...Certain Materials § 148.227 Calcium nitrate fertilizers. This part does not apply to commercial grades of calcium nitrate fertilizers consisting...

2014-10-01

454

10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.  

Code of Federal Regulations, 2014 CFR

...Amount of financial protection required for plutonium processing and fuel fabrication plants...Amount of financial protection required for plutonium processing and fuel fabrication plants...70 of this chapter to possess and use plutonium at a plutonium processing and...

2014-01-01

455

10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.  

Code of Federal Regulations, 2012 CFR

...Amount of financial protection required for plutonium processing and fuel fabrication plants...Amount of financial protection required for plutonium processing and fuel fabrication plants...70 of this chapter to possess and use plutonium at a plutonium processing and...

2012-01-01

456

10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.  

Code of Federal Regulations, 2013 CFR

...Amount of financial protection required for plutonium processing and fuel fabrication plants...Amount of financial protection required for plutonium processing and fuel fabrication plants...70 of this chapter to possess and use plutonium at a plutonium processing and...

2013-01-01

457

10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.  

Code of Federal Regulations, 2011 CFR

...Amount of financial protection required for plutonium processing and fuel fabrication plants...Amount of financial protection required for plutonium processing and fuel fabrication plants...70 of this chapter to possess and use plutonium at a plutonium processing and...

2011-01-01

458

10 CFR 140.13a - Amount of financial protection required for plutonium processing and fuel fabrication plants.  

Code of Federal Regulations, 2010 CFR

...Amount of financial protection required for plutonium processing and fuel fabrication plants...Amount of financial protection required for plutonium processing and fuel fabrication plants...70 of this chapter to possess and use plutonium at a plutonium processing and...

2010-01-01

459

Plutonium disposition via immobilization in ceramic or glass  

SciTech Connect

The management of surplus weapons plutonium is an important and urgent task with profound environmental, national, and international security implications. In the aftermath of the Cold War, Presidential Policy Directive 13, and various analyses by renown scientific, technical, and international policy organizations have brought about a focused effort within the Department of Energy to identify and implement paths for the long term disposition of surplus weapons- usable plutonium. The central goal of this effort is to render surplus weapons plutonium as inaccessible and unattractive for reuse in nuclear weapons as the much larger and growing stock of plutonium contained in spent fuel from civilian reactors. One disposition option being considered for surplus plutonium is immobilization, in which the plutonium would be incorporated into a glass or ceramic material that would ultimately be entombed permanently in a geologic repository for high-level waste.

Gray, L.W.; Kan, T.; Shaw, H.F.; Armantrout, A.

1997-03-05

460

Plutonium fractionation in southern Baltic Sea sediments.  

PubMed

In this study, different chemical plutonium fractions (dissolved in water, connected to carbonates, connected to oxides, complexed with organic matter, mineral acids soluble and the rest) in sediments from the Vistula River estuary, the Gda?sk Basin and the Bornholm Deep were determined. The distribution of (239+240)Pu in analysed sediments samples was not uniform but dependent on its chemical form, depth and the sediment geomorphology. The highest amount of plutonium exists in middle parts of sediments and comes from the global atmospheric fallout from nuclear tests in 1958-1961. According to all analysed fractions, the biggest amount of (239+240)Pu was in the mobile form, connected to carbonate fractions from the Vistula River estuary, the Gulf of Gda?sk and the Bornholm Deep sediments. PMID:22612422

Strumi?ska-Parulska, Dagmara I; Skwarzec, Bogdan; Pawlukowska, Magdalena

2012-01-01