New fecal method for plutonium and americium

A new fecal analysis method that dissolves plutonium oxide was developedat the Westinghouse Savannah River Site. Diphonix Resin . (Eichrom Technologies),is used to pre-concentrate the actinides from digested fecal samples. A rapidmicrowave digestion technique is used to remove the actinides from the DiphonixResin ., which effectively extracts plutonium and americium from acidic solutionscontaining hydrofluoric acid. After resin digestion, the plutonium and americiumare recovered in a small volume of nitric acid that is loaded onto small extractionchromatography columns, TEVA Resin and TRU Resin (Eichrom Technologies). Themethod enables complete dissolution of plutonium oxide and provides high recoveryof plutonium and americium with good removal of thorium isotopes such as ²²⁸Th.     

Automated radiochemical procedure for plutonium and americium measurement

A radiochemical separation method for plutonium and americium from aqueous medium has been developed using a pre-packed resin column, a peristaltic pump, and the necessary tubing and valves for flow injection technique. All the radioanalytical operations were conducted in-line. Samples made of plutonium and americium tracers in water were analyzed by this technique and counted by alpha spectroscopy. The results show that plutonium and americium can be measured simultaneously using this technique.     

Concentration factors of plutonium and americium for marine products

For a realistic dose estimation, we derived the concentration factors (CF) of plutonium and americium for the field measurements of marine products and ambient coastal sea water.The distribution of the concentration ratios (CR) between the concentration in marine products and that in ambient sea water shows a lognormal distribution. The concentration factors of plutonium and americium which are derived as the geometric mean of CR values, are 231 and 67 for whitebait, 12 and 37 for flatfish, 350 and 220 for brown algea, 140 and 670 for shell fish, 27 and 130 for cephalopods, and 250 and 550 for crustaceans, respectively.     

A novel approach for extraction of plutonium and americium from aqueous complexing media

Journal of Radioanalytical and Nuclear Chemistry - A new approach for the extraction of plutonium and americium from aqueous media containing complexing ligands has been investigated using a new...     

Studies for simultaneous quantitative electrodeposition of plutonium and americium for alpha-spectrometry

For high resolution alpha-spectrometric studies, the sources of alpha-emitting actinides are generally prepared by electrodeposition. Usually, by electrodeposition of only one element can be achieved quantitatively. A method was developed for the simultaneous quantitative electrodeposition of plutonium and americium, in two hours using 0.005M oxalic acid with saturated ammonium chloride. The alpha-spectral characteristics of sources prepared by this method were better than those prepared by the drop deposition method. This electrodeposition procedure was validated with nuclear fuel samples containing plutonium and americium.     

A robust procedure for the determination of plutonium and americium in seawater

A new procedure for the analysis of Pu and Am in large water samples is presented. In this procedure, the actinides are first preconcentrated from 200 liter water samples with combined MnO₂ and Fe(OH)₃ co-precipitation. Pu and Am are then separated from the large amount of Mn by performing a second precipitation of Fe(OH)₃ at pH 6. The final separation of Pu and Am from interfering elements and from each other is achieved with the use of a single extraction chromatographic column of TRU-ResinÔ. The -activities are then determined using -spectrometry after source preparation by CeF₃ micro co-precipitation. The procedure described is faster, simpler, more robust and gives higher chemical yields then procedures normally used for routine analysis of Pu and Am. The chemical yields of Pu and Am, when analysing 200 liter sea water samples, are between 80-85%.     

Simultaneous biphasic liquid scintillation determination of americium and plutonium

A procedure for the simultaneous determination of²⁴¹Am and²³⁹Pu or²³⁸Pu was carried out in samples such as air filters, sweep-tests, aqueous solutions and urine. The method described here includes a previous treatment of the samples in accordance with the type of matrix in which the actinides are included and a liquid scintillation counting using a two-phase cocktail. The upper detection limit was estimated to be 50 mBq for a 50-minute counting time.     

Preconcentration of plutonium and americium using the Actinide-CUTM Resin for human tissue analysis

A method for the preconcentration of Am and Pu from human tissue solutions (liver, lung, bone etc) using the Actinide-CU Resin (ElChroM Industries) has been developed for their alpha-spectrometric determination. With near 100% recoveries were obtained by preconcentration, subsequent decomposition methods for eluent were developed. Good agreement for Pu and Am determination with the USTUR anion-exchange/solvent extraction method was demonstrated using previously analyzed human tissue solutions and NIST SRMs. The advantages of the preconcentration method applied to human tissue analysis are simplicity of operation, shorter analysis time compared to anion exchange/solvent extraction methods, and capacity to analyze large tissue samples (up to 15 g bone ash per analysis and 500 g soft tissue).     

Purification of americium from bulk quantities of plutonium loading effluent using trilaurylamine

Four litres of Am solution containing 81.5 mg/l Am and 0.6 mg/l Pu could be purified by a two-step procedure involving solvent extraction and extraction chromatography with trilaurylamine. The final product contained a maximum concentration of 9 g/l Pu.     

Direct-scanning alpha-spectrometer for americium and plutonium contamination on highly-enriched uranium surfaces

Trace²³⁹Pu and²⁴¹Am contamination on a surface whose alpha count is dominated by²³⁵U and²³⁴U decay has been successfully quantified by counting swipes in external alpha-spectroscopy chambers. The swipe process, however, is labor intensive and subject to uncertainties in the swiping process as well as degraded spectral resolution due to the presence of the swipe material. A multichannel instrument for automated in situ measurements of interior and exterior contamination has been developed which incorporates a rotary table, 13 fixed ion-implanted silicon detectors, and spectroscopy electronics. Custom software was written to allow alpha-spectrometer to function as a virtual instrument in the LabView environment. This system gives improved speed and resolution as well as a complete log of the location of areas of high surface contamination, a feature not practical to obtain by other methods, and one which opens the possibility of long term studies such as Pu outgrowth evaluation employing the instrument. We present performance data as well as system integration, calibration, control, and dynamic geometric efficiency calculations related to the design of this and next generation systems.     

Removal of plutonium and americium from oxalate supernatants by co-precipitation with thorium oxalate

As a part of treatment of low level active waste, co-precipitation of plutonium (Pu) and americium (Am), with thorium oxalate, from oxalate supernatants generated during plutonium oxalate precipitation has been investigated. A simple method for the simultaneous removal of both Pu and Am from oxalate supernatants could be developed. This simple process achieves incorporation of these alpha active nuclides into small volumes of solid matrix from large volumes of aqueous waste.     

Determination of plutonium and americium in moss and lichen samples

A simple, sensitive and selective method is described for the simultaneous determination of plutonium and americium in lichen and moss samples which can be used as the atmospheric radioactivity bioindicators. Plutonium is separated from a HCl leaching solution by a Microthene-TNOA column; americium is separated by a KL-HDEHP column and purified by PMBP-TOPO extraction. A special attention has been paid to the decontamination of plutonium and americium from²¹⁰Po. Ten lichen and 12 moss samples from tree trunks have been analyzed: starting from 2 g sample, the average yields and the detection limits were 70.2±12.5% and 28 mBq/kg for plutonium and 70.0±15.1% and 34 mBq/kg for americium. The concentrations (mBq/kg) ranged from 28 to 4960 for^239,240Pu, from 28 to 171 for²³⁸Pu and from 34 to 1930 for²⁴¹Am, respectively.     

Preparation, characterization and application of thorium oxalate for sorption of plutonium and americium from aqueous solution

Synthetic inorganic exchangers exhibit good thermal and radiation stability. Thorium oxalate precipitate shows potential for co-precipitation of plutonium and americium from oxalate supernatant generated during plutonium oxalate precipitation. In the present study, efforts were made to prepare thorium oxalate precipitate to be used for column operation. Distribution ratios were determined to optimize conditions for sorption of plutonium and americium on thorium oxalate from nitric acid + oxalic acid solutions with composition similar to that of oxalate supernatant. Column experiments were also performed to evaluate the sorption capacity of thorium oxalate for plutonium and americium from the same medium. The result showed that, thorium oxalate prepared in 1.75M HNO₃ at 70 °C is suitable for column operations. These studies showed that plutonium and americium could be simultaneously removed from aqueous solutions with composition similar to plutonium oxalate waste using glass column packed with thorium oxalate and these nuclides could be recovered by eluting with 3M HNO₃.     

Alpha spectrum evaluation method for the simultaneous determination of plutonium,americium and curium

A method based on the geometric progression decrease of the counts in the far tail of the alpha spectrum is described for the simultaneous determination of plutonium, americium and curium by alpha spectrometry. For evaluating the precision and accuracy, synthetic mixtures were prepared from solutions of enriched isotopes and sources were prepared by direct evaporation method using tetraethylene glycol /TEG/ as a spreading agent and electropolished stainless steel discs as the backing material. Precision and accuracy of about 1% is demonstrated in the determination of²⁴⁴Cm/²³⁹Pu,²⁴¹Am/²³⁹Pu,²⁴⁴Cm/²³³U,²⁴¹Am/²³³U and²³⁹Pu/²³³U alpha activity ratios using a 450 mm² silicon surface barrier detector.     

Elevated plutonium and americium content in skulls of small mammals

It has been found that in skull bones of small mammals have significantly higher Pu and Am concentrations than ever found in bones of any other species in areas contaminated by global fallout. Since there was no difference between skulls of rodents and insectivorous, an explanation is proposed that the contamination takes place by the inhalation of Pu and Am tiny soil particles.     

Determination of plutonium,americium and curium in environmental meterials

A sequential radiochemical scheme for the separation of Pu and Am (along with Cm) from environmental materials is given. Optimum conditions for coprecipitation of these elements on bismuth phosphate and the influence of Fe and Th content of the sample on the recovery of Am were studied. Internal tracers²⁴²Pu and²⁴³Am were used as tracers for Pu and Am, respectively, and estimates were made by alpha-spectrometry. Average recoveries obtained from sea water were 85% and 77% for Pu and Am, respectively. Lower recoveries (<50%) were obtained for Am in sediments. Work carried out as part of the International Atomic Energy Agency Research Contract 1954/RB/RI.     

Experimental measurements of short-lived fission products from uranium,neptunium, plutonium and americium

Fission yields are especially well characterized for long-lived fission products. Modeling techniques incorporate numerous assumptions and can be used to deduce information about the distribution of short-lived fission products. This work is an attempt to gather experimental (model-independent) data on short-lived fission products. Fissile isotopes of uranium, neptunium, plutonium and americium were irradiated under pulse conditions at the Washington State University 1 MW TRIGA reactor to achieve ~10⁸ fissions. The samples were placed on an HPGe (high purity germanium) detector to initiate counting in less than 3 min post irradiation. The data was analyzed to determine which radionuclides could be quantified and compared to the published fission yield data.     

Simultaneous recovery of plutonium and americium from assorted analytical waste solutions using extraction chromatography

A rapid extraction chromatography based methodology was developed for simultaneous recovery of plutonium and americium from various kinds of analytical waste obtained during chemical quality control of plutonium based nuclear materials using sulphonic acid based actinide? resin. Efforts were made to understand the effect of initial feed acidity, gamma radiation and the concentrations of Am³⁺ and Pu⁴⁺ on their k _d. values. Processing of assorted analytical waste solutions through this method revealed that more than 95 % of Am³⁺ and 90 % of Pu⁴⁺ were adsorbed on the resin while iso- propanol can be successfully employed for the quantitative recovery of both the actinides from the loaded resin phase.     

Periodic trends in lanthanide and actinide phosphonates: discontinuity between plutonium and americium

The hydrothermal reactions of trivalent lanthanide and actinide chlorides with 1,2-methylenediphosphonic acid (C1P2) in the presence of NaOH or NaNO(3) result in the crystallization of three structure types: RE[CH(2)(PO(3)H(0.5))(2)] (RE = La, Ce, Pr, Nd, Sm; Pu) (A type), NaRE(H(2)O)[CH(2)(PO(3))(2)] (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy; Am) (B type), or NaLn[CH(2)(PO(3)H(0.5))(2)]·(H(2)O) (Ln = Yb and Lu) (C type). These crystals were analyzed using single crystal X-ray diffraction, and the structures were used directly for detailed bonding calculations. These phases form three-dimensional frameworks. In both A and B, the metal centers are found in REO(8) polyhedra as parts of edge-sharing chains or edge-sharing dimers, respectively. Polyhedron shape calculations reveal that A favors a D(2d) dodecahedron while B adopts a C(2v) geometry. In C, Yb and Lu only form isolated MO(6) octahedra. Such differences in terms of structure topology and coordination geometry are discussed in detail to reveal periodic deviations between the lanthanide and actinide series. Absorption spectra for the Pu(III) and Am(III) compounds are also reported. Electronic structure calculations with multireference methods, CASSCF, and density functional theory, DFT, reveal localization of the An 5f orbitals, but natural bond orbital and natural population analyses at the DFT level illustrate unique occupancy of the An 6d orbitals, as well as larger occupancy of the Pu 5f orbitals compared to the Am 5f orbitals.