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In this work, the resin capacity factors of Ac, Am and Th on the DGA extraction chromatographic resin have been investigated between 0.5 and 2.0 M nitric acid without and with addition of elevated concentrations of the selective tetravalent complexant, 343HOPO. The resin capacity factors decreased with increasing 343HOPO concentration but remained high enough to support a selective removal of a tetravalent element. The Ac and Am capacity factors were also investigated under Th loading which yields generally reduced uptake on the resin. It was shown that loading effects could be fully scavenged by the addition of 343HOPO complexant. These results indicate that separation steps for Ac involving significant amounts of Th can be handled by selective tetravalent complexation with the DGA system.

In this work, a simple and efficient procedure for the mutual separation of trivalent americium and curium (Am(III) and Cm(III)) has been provided by extraction chromatography with the novel developed XAD-7-based BCPDTPA composite sorbent in nitric acid solution. The batch experiments and column separation studies were systematically performed. The influences of nitric acid concentration and temperature on the weight distribution coefficients and separation factors for Am(III) and Cm(III) were determined in the batch experiments. Based on the data in the batch studies, the column experiments were designed and conducted. A satisfactory separation of Am(III) and Cm(III) was accomplished in a 1.4 mL column (φ5 × 70 mm) with 0.10 mol L−1 nitric acid solution. It is noted that the partitioning process can work with single nitric acid solution without any additives.

The component additive model UNiSeCs II for simulating the physicochemical behaviour of the radionuclides americium, plutonium and selenium in agricultural soils is presented. The model is validated by estimating the distribution coefficients (Kd) of these elements measured in batch experiments from the literature. For all three elements, the resulting average relative deviations from the experimental values are smaller than a factor of 2.5. This indicates that the model has the potential to significantly improve the predictions of radioecological models that normally use tabulated Kd values from the IAEA which are known to have large uncertainties. Using UNiSeCs II, the soil solution parameters most important for the partitioning of Am, Pu and Se are identified by single parameter variations.

The Joint Research Centre, in cooperation with the Commissariat à l’Energie Atomique et aux Energies Alternatives, produced a novel243Am spike reference material for mass spectrometry. Americium solution with an isotopic composition of 88%243Am and 12%241Am was used as the source for the preparation of the spike material. The certified value of 5.696 (11) nmol g−1for the amount content of243Am and 0.136138 (54) for then(241Am)/n(243Am) amount ratio were assigned. The assigned values from mass spectrometry were confirmed by alpha-particle spectrometry, alpha-particle counting at a defined solid angle, and high-resolution gamma-ray spectrometry. Furthermore, an external validation of the certified values was obtained from the results of an interlaboratory comparison exercise, using this americium reference solution as the test sample.

To achieve trichotomic separation of light lanthanides (Ln), heavy Ln, and Am, batchwise multi-stage extractions using N,N,N′,N′-tetraoctyl-diglycolamide (TODGA) extractant from organic acids are studied. This technique has the advantages of both solvent extraction and chromatography, which enable successive separation and management of large volumes of aqueous solutions. Malonic acid (M-Acid) is used as the main component of the aqueous phase. It is clear that the separation factor for Nd/Am from M-Acid and that for La/Am from M-Acid + HNO3 are both around 30, thus we plan to conduct these separations.

The half-life of 243Am has been measured by an absolute and a relative method, i.e. by determining the specific activity of 243Am and the specific activity ratio with 241Am. A mixed 241,243Am reference material was produced and certified for its americium mass content and its isotope amount ratios. The characterisation of the mass content of 243Am was established by isotope dilution mass spectrometry using an 241Am spike, produced from highly enriched 241Pu material. The isotope amount ratios n(241Am)/n(243Am) and n(242mAm)/n(243Am) were measured by thermal ionisation mass spectrometry. Activity measurements were performed by alpha-particle counting at a defined solid angle, as well as high-resolution alpha-particle spectrometry. From the 243Am/241Am activity and isotopic amount ratios, a value of 16.988 (24) was derived for the 243Am/241Am half-life ratio. Using a value of 432.6 (6) a for the 241Am half-life, the corresponding 243Am half-life value, 7349 (15) a, is in good agreement with the result obtained from the absolute method, 7342 (14) a. The mean value, 7345 (14) a, agrees well with data from literature and lowers the relative standard uncertainty to 0.2%.

A novel method has been developed for the simultaneous determination of uranium, plutonium and americium nuclides in soil and sediment samples up to 5 g. Samples are destroyed by fusion with sodium hydroxide. Pre-concentration procedure tailored to the extraction chromatography is based on co-precipitation of actinides and removal of silica, iron and calcium. For the sequential separation of actinides a single DGA resin® (containing N,N,N′,N′-tetra-n-octyldiglycol-amide) column is used. Separation of americium from lanthanides is inherently involved in the EC procedure. Alpha sources are prepared from the individual actinides strip solutions. High recoveries (above 75%) and sensitivities (about 0.1 Bq/kg) have been obtained to allow the determination of actinides of environmental levels. The whole procedure can be performed in 2 days.

This paper reported creating the all-chromatographic technique for the recovery of americium radionuclides from solutions of the complex composition generated in the radiochemical industry. The technique was based entirely on the displacement complexing chromatography; neither additional precipitation nor extraction stages were necessary. The technology used the elution with DTPA and NTA-based solutions containing the citric acid additives and the sequential elution with these eluents, emphasizing the separation of americium from the heavy rare earth elements, lead, and cadmium. The complete separation of americium from lead and cadmium was a peculiar exercise; the elution order of lead and cadmium changed in the presence of the citric acid additives. The recovery and separation of americium from actual radioactive waste solutions of different origins demonstrated 96 and 99% chemical purity of the final product.

Liquid–liquid extraction (LLE) of microamounts of americium(III) from Na2CO3 and Na2CO3–H2O2 aqueous solution using methyltrioctylammonium (MTOA) carbonate in toluene has been studied. The distribution ratio of americium(III) into the organic phase can reach values of > 200 from aqueous phases of dilute Na2CO3 and H2O2. With an increase in concentration of Na2CO3 and H2O2 the value of distribution ratio of americium(III) decreases. The stoichiometry of the extracted species of americium(III) was determined on the basis of the slope analysis method. The extracted species are R4N[Am(CO3)2] and (R4N)3[Am(CO3)3], where R4N is MTOA.

The effect of γ-radiation on the extraction properties of two functionalized calixarenes (p-tert-butyl-thiacalix[4]arene and p-tert-butylcalix[8]arene) is studied. The most characteristic products of the irradiated extractants interaction with diluent are identified by mass spectrometry. Extraction ability of studied calixarenes towards cesium and americium before and after irradiation is evaluated. Quantitative analysis of chloride and sulfate ions after irradiation is performed to estimate the radiological degradation degree of components. Irradiation has different effect on p-tert-butyl-thiacalix[4]arene and p-tert-butylcalix[8]arene extraction ability towards americium, which may be due to the nature and extraction ability of radiolysis products, and practically does not affect cesium extraction.

Macroporous Me2-CA-BTP/SiO2-P was used for separating 241Am(III) from lanthanides. Good selectivity towards 241Am(III) was achieved in 0.1–3 M HNO3. Adsorption equilibrium of 241Am(III) was obtained within 1 h in 0.1 M HNO3 solution. 241Am(III) was efficiently separated from lanthanides through column experiment in both 0.1 M HNO3 and 0.01 M HNO3–0.34 M NaNO3 solution. It still performed excellently at 207 kGy under γ irradiation in nitrate medium. In a word, Me2-CA-BTP/SiO2-P is a very promising candidate for separating MA from Ln that even a salt-free Ln&MA separation process may be established such as from 0.1 M HNO3 based on it.

A method intended for the mg scale separation of curium (Cm) from americium (Am) and plutonium (Pu) based on high pressure liquid chromatography using a strong cation exchange column has been investigated. Reproducible separations were achieved on the Luna SCX (Phenomenex) column with α-hydroxymethylbutyric acid (α-HMBA) as eluant. The separation performance was investigated on the tracer level varying the pH, concentration, temperature and flow rate of the eluting solution. It was found that 0.1 M α-HMBA at a pH of 3.7 using a flow-rate of 1 mL/min, gave enough peak resolution for an efficient and reproducible separation of Cm from Am. Separations with gadolinium loading were investigated to scale up the purification of Cm from tracer level to mg scale. Baseline chromatographic separations were demonstrated in column loadings of up to 20% of full column capacity, corresponding to 2.5 mg of Cm.

Rapid methods for determination of internal contamination play a key role during emergency situations in particular for incident response teams and affected populations. For this reason, these methods and their particular techniques must be fast, reliable, robust, simple and cost-efficient, as well as providing high-quality throughput. On the other hand, they are characterized by lower precision and they are often biased. The presented method is based on direct measurement of urine using powder scintillator YAP:Ce together with an alkaline medium as a replacement for traditional liquid scintillation cocktail. The overall efficiencies for trivalent actinides (Am-241 and Cm-244) were greater than 85% and 94%.

Radiolytic stability of polymeric resins is an important aspects in nuclear materials processing. The different dosage of gamma radiation was subjected to meta-polybenzimidazole (m-PBI), para-polybenzimidazole (p-PBI) and pyridine-m-PBI based polymeric resins, which was taken for the present radiolytic stability investigation. Irradiated polymers were characterized by FT-IR, SEM and TGA analysis. Extraction of U(IV) and Pd(II) as a function of nitric acid concentration using 50, 100 and 150 kGy gamma irradiated polymeric resins was carried out and static capacity was also investigated for the gamma irradiated polymeric resins and compared with their unirradiated ones. In addition, the extraction behaviour of radionuclides, namely, plutonium, americium and europium as a function of HNO3 concentration utilizing both unirradiated and 150 kGy gamma irradiated polymeric resins was studied for the first time. Results indicated that FT-IR spectra of both unirradiated and 150 kGy irradiated resins are similar. TGA analysis revealed 50% and 20% weight loss for pyridine-m-PBI, m-PBI, respectively. The distribution ratio values decreases with increase in gamma irradiation. The uranium and palladium static capacities were found to be 30 and 182 mg/g resin, respectively. The overall results indicated that p-PBI resin has higher extraction efficiency and exhibits better radiation resistant behaviour as compared to pyridine-m-PBI and m-PBI.

A new method was developed to effectively separate Am(III) from Cm(III). Am(III) was selectively oxidized to Am(V) using a mixture of Na2S2O8, Ag(I), and NaOCl in 0.01 M HNO3. Cm(III) was selectively retained on a DGA resin, while Am(V) had no retention. A separation factor of 110 ± 20 was usually obtained from a single separation. The new separation method was applied to determine Cm isotopes 244, 245 and 246 by accelerator mass spectrometry (AMS) in spent nuclear fuel samples.

Interactions of components of the multibarrier safety system of an underground repository environment are important factors for safety assessments. Na–Al–P glass is the major high level waste (HLW) matrix in Russia. Degradation of HLW glass causes an increase of phosphate concentration in water that influences on radionuclides speciation. Americium is important in HLW. In the presence of phosphate in synthetic groundwater almost half of the americium present is in colloidal matter and its sorption onto clay is slightly decreased relative to the absence of phosphate. The presence of phosphates in the system of synthetic groundwater—clay during sorption experiments significantly affected on the solid-phase speciation and led to an increase in the proportion of strongly bound americium.

Nanoparticles of metal oxides with high specific surface area were tested for separation of selected radionuclides (241Am, 60Co, 137Cs and 90Sr) from simulated spent decontamination solutions containing citric acid. The following materials, prepared via photoinduced synthesis, were tested: NiO, NiO/TiO2 and ZnO:Cu. Buffer solutions with concentration of citric anions 0.01 mol l−1 were used in the tests. Sorption properties were investigated in pH range 2–12. Additionally, the influence of surfactants on the sorption was studied. The results obtained show the highest retention of radionuclides for nanoparticles of NiO/TiO2 at basic pH.

Alpha spectrometry is used for qualitative and quantitative analysis of actinides in biological and environmental samples. This technique requires a thin, homogenous and carrier-free deposit. Numerous methods for source preparation are electrolytic deposition, spontaneous deposition, micro-precipitation, direct evaporation, vacuum sublimation, etc. The most widely used method for preparation of actinides for alpha spectrometry is electro-deposition of actinides onto a stainless steel planchette. This procedure is time consuming, requires elaborate equipment and is expensive. Micro-precipitation method on the other hand is comparatively faster and more reliable. Thus, the present study was taken-up to optimize various parameters for rapid alpha source preparation of actinides by micro-precipitation method.

Rapid measurement of transplutonium isotopic mass distributions during 252Cf production campaigns at Oak Ridge National Laboratory is a critical need. Mass measurements for the isotopes of plutonium, americium, curium, and californium are routinely requested to support the α-hydroxy-isobutyrate runs for the purification and recovery of the heavy curium target material and final 249Bk, 252Cf, and 254Es enriched isotope products. This paper presents the integration of an online high-pressure ion chromatography inductively coupled plasma mass spectrometry technique together with the protocol and chemistry that allows for rapid baseline separation and direct quantification of the transplutonium elemental concentrations and isotopic compositions.

The retention of americium and plutonium on six commercially available extraction chromatographic resins was investigated in the presence of various concentrations of calcium. Results of batch study experiments showed that there was no significant interference due to calcium for the adsorption of plutonium or americium from both nitric and hydrochloric acid on the majority of the extraction chromatographic resins studied. However, the retention of americium on DGA resin from nitric acid decreased by over two orders of magnitude when calcium was introduced into the system. DGA was found to have a capacity for calcium of 4.53 ± 0.08 mg Ca g−1 DGA resin.

The extraction of trivalent europium and americium in the system water—HNO3—3-nitro-α,α,α-trifluorotoluene (F-3)—bis-1,2-dicarbollylcobaltate—N,N,N′,N′-tetraoctyl diglycolamide (L) has been investigated. The experimental data were treated by curve-fitting method using the LETAGROP program. It has been found that the complexes $${\text{HL}}_{{}}^{ + }$$ , $${\text{HL}}_{2}^{ + }$$ , $${\text{ML}}_{ 2}^{3 + }$$ , $${\text{ML}}_{ 3}^{3 + }$$ and $${\text{ML}}_{ 4}^{3 + }$$ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in F-3 saturated with water have been determined. Extraction in this system can be used for separation of lanthanides and minor actinides from PUREX process raffinate.

A new approach for the extraction of plutonium and americium from aqueous media containing complexing ligands has been investigated using a new extractant N,N′-dioctyl-α-hydroxy acetamide. Studies have been carried out on the extraction of Am(III) and Pu(IV) by this extractant from media containing complexing ligands such as PO43−, C2O42− and F− which are difficult to extract due to the non-extractability of the complexed form of these metal ions. Present study has revealed that, addition of non-complexing anions such as ClO4−, I−, SCN− into the medium containing complexing ligand greatly enhanced extraction of Pu(IV) and Am(III), making the extraction of these nuclides possible.

The performance of a series of novel O-phenoxydiamides extracting Zr(IV), Eu(III), U(VI), Pu(IV) and Am(III) was studied. The result of extraction experiments showed that the coordination abilities of these five congeneric O-phenoxydiamides decrease in the order of CycleDODA > PhenylDODA > ButylDODA > HexylDODA > BenzoDODA, the abilities of different metal ions coordinating with the same ligand decrease in the order of Pu(IV) ≫ U(VI) > Zr(IV), Eu(III), Am(III). At HNO3 concentration of 5.0 mol/L, the distribution ratio of BenzoDODA/n-dodecane extracting Pu(IV) is much larger than those of other metal ions, the separation factors of Pu(IV) over Eu(III), Zr(IV), U(VI) and Am(III) are between 20 and 300, which can be used for recovering Pu(IV) selectively from highly acidic liquid waste. The density functional theory (DFT) calculation of the 25 complexes in geometrical structure, Mayer bond order (MBO) and energy was further studied, the result is consistent with the experimental result.

Extraction of actinides from aqueous nitric acid by three different heterocyclic dicarboxamides (2,6-pyridinedicarboxamide, 2,2′-bipyridine-6,6′-dicarboxamide and 1,10-phenanthroline-2,9-dicarboxamides) was studied. It was shown that all studied ligands extract actinides at different oxidation states (U(VI), Np(V), Pu(IV), Am(III), Cm(III)) from acidic solutions. All studied diamides extract Am(III) better than Cm(III). Et(pHexPh)ClPhen contains electron-withdrawing chlorine atoms at the positions 4 and 7 of the phenanthroline moiety (SFAm/Cm = 4–6) and possesses the highest separation factor Am(III)/Cm(III). The studied ligands possess high extraction ability to all actinides present in HLW and therefore they could be used for simultaneous extraction of actinides in the GANEX-type process.

Separating the minor actinide elements (americium and curium) from the fission product lanthanides is an important step in closing the nuclear fuel cycle. Isolating the minor actinides will allow transmuting them to short lived or stable isotopes in fast reactors, thereby reducing the long-term hazard associated with these elements. The Actinide Lanthanide Separation Process (ALSEP) is being developed by the DOE-NE Material Recovery and Waste Form Development Campaign. The impact of gamma radiolysis upon the efficacy of the ALSEP process was previously evaluated by determining americium, europium, and cerium distribution ratios as a function of absorbed dose using samples taken from this set of test loop irradiations. The measured distribution ratios demonstrated that the ALSEP solvent performance was degraded by γ-irradiation. The compositional analysis of the irradiated ALSEP solvent samples revealed that the decrease in americium, europium, and cerium distribution ratio with increasing absorbed dose is primarily attributable to the loss of the T2EHDGA extractant due to radiolytic degradation.

Extraction efficiency of uranium and transuranium elements (Np, Pu, Am and Cm) with tert-butylthiacalix[4]arene TCA from carbonate-alkaline solutions is studied and compared with that of europium (III). Plutonium (III, IV) extraction efficiency with TCA is found to be lower comparing with that of trivalent americium and europium. Extraction efficiency of studied radionuclides decreases as following: Am ≫ Eu ≫ Pu (III), U(VI), Np (V) > Pu (IV) at pH 12. Carbonate concentration increase in aqueous phase suppresses significantly extraction of all studied radionuclides, except americium. This condition can be used for americium individual recovery from complex radioactive carbonate-alkaline solutions.

The trivalent actinide selective neutral extractants such as carbamoylmethylphosphine oxide (CMPO) and bis-(2-ethylhexyl)diglycolamide (TEHDGA) in conjunction with an acidic extractant bis-2-ethylhexylphosphoric acid (HDEHP) have been impregnated in Tulsion ADS 400, and the resultant solvent impregnated resin (SIR) has been evaluated for the radiolytic stability towards gamma radiation. The extraction behavior of Am(III) and the loading behavior of Eu(III) in the SIR was studied as a function of absorbed dose up to 550 kGy, at different nitric acid concentrations in aqueous phase. The extraction isotherm of Eu(III) in various SIRs have been fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) adsorption models. The extraction results and modeling of extraction isotherms obtained at various absorbed dose levels have been reported in this paper.

As a long-lived radionuclide, americium (Am) in spent nuclear fuel is a tricky isotope that partially impedes nuclear waste reclamation. This study dealt with sorption of europium (Eu) as a nonradioactive surrogate for Am onto diethylenetriaminepentaacetic acid based SiO2 (DTPA-SiO2). Equilibrium isotherms, kinetics, thermodynamics and pH experiments were investigated batch wise. The sorption strongly depended on pH. The maximal europium sorption capacity reached 192.42 mg/g, much higher than any currently reported. Thermodynamic parameters suggested the sorption was a spontaneous, exothermic and entropy increase process. Regeneration results showed the acceptable loss in the sorption ability after five circulations, indicating good reusability.

The extraction behaviour of Am(III) and other metal ions present in the fast reactor simulated high- level liquid waste (FR-SHLLW) was studied using a modifier-free solvent phase composed of N,N-di-octyl-2-hydroxyacetamide (DOHyA) in n-dodecane. Quantitative extraction of Am(III) was achieved with the co-extraction of all lanthanides, Y(III) and Mo(VI) in the first five stages of a 20-stage mixer-settler. During the stripping run with 0.5 M HNO3, Am(III), Ln(III) and Y(III) were quantitatively transferred to the aqueous product in three stages. The other extracted metal ions were retained in organic phase. The results showed that the extraction performance of DOHyA was superior to other amide extractant systems reported in the literature.

137Cs and 241Am extraction with perchloroethylene solutions of O-substituted p-alkylcalix[8]arenes (alkyl: tert-butyl, iso-nonyl) from carbonate-alkaline media is studied. Dependence of distribution ratios on pH values of the aqueous phase in the range 11–13.9 and on the nature of functional groups in the calixarene platform is confirmed. Composition of cesium and americium solvates with calix[8]arenes is determined. Tert-butylcalix[8]arene with oxybis(ethane-1,2-diyl) bridging group possesses superior efficiency towards cesium in alkaline media. The most efficient extractants for americium are “mixed” iso-nonyl-tert-butylcalix[8]arenes with ethane-1,2-diyl and oxybis(ethane-1,2-diyl) bridging groups.

A method using DGA resin (N,N,N′,N′-tetra-n-octyldiglycolamide on an inert support) was developed for the rapid analysis of actinides in urine samples. Samples acidified with HCl to 4 M were loaded directly (without digestion) onto a DGA column. Actinides were stripped simultaneously, α-sources were prepared by co-precipitation with NdF3. Americium, plutonium and uranium were separated with acceptable high recoveries (40–80%). The americium, plutonium and uranium content of 100–200 ml urine samples was determined within 24 h with detection limits as low as 0.01 Bq l−1. Based on model experiments using 14C-spiked urea, it was proven that high urea content can affect americium separation deleteriously due to irreversible fixing of americium on DGA resin.

The separation of americium(III) from europium(III) was achieved utilizing a bis-2,6-(5,6,7,8-tetrahydro-5,9,9-trimethyl-5,8-methano-1,2,4-benzotriazin-3-yl) pyridine (CA-BTP) chromatographic resin. The extraction chromatographic materials were prepared using various concentrations of CA-BTP. This new, hydrolytically stable extractant was impregnated on an inert polymeric support at 40% loading. The uptake of Am(III) and Eu(III) by this material from 0.1 to 4.0 M aqueous HNO3 solutions was measured. The resulting dry weight distribution ratios, D w , indicated a strong preference for Am(III) with little affinity for Eu(III). These results are similar to recently reported solvent extraction studies indicating a maximum uptake of Am(III) in the 0.5–1.0 M HNO3 range. The resin preparation, performance, and characterization of the Am/Eu separation are reported herein.

Co-precipitation of plutonium and americium from nitric acid–oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from plutonium oxalate waste solutions and anion exchange effluents respectively. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate from a wide range of nitric acid and oxalic acid concentrations indicate feasibility of direct treatment of oxalate waste solutions and anion exchange effluents by this method. Co-precipitation of Am(III) from high nitric acid concentrations is poor, however, this could be effectively achieved, after partially neutralizing the acid with ammonia.

Two diglycolamide homologs, N,N,N′,N′-tetraoctyl-3,6-dioxaoctane diamide (DOODA) and N,N,N′,N′-tetraoctyl-3,6,9-trioxaundecane diamide (TOUDA), were synthesized. Their extraction behaviors of Am3+ and Eu3+ were investigated and compared with those of N,N,N′,N′-tetraoctyl-3-oxapentane diamide (TODGA). The extraction ability toward Am3+ and Eu3+ decreased with increasing etheric oxygen number in the extractant structure. In contrast to TODGA, an very interesting inversion on the selectivity occurred for DOODA and TOUDA, which were more favor of extracting Am3+ than Eu3+. The maximum SF Am/Eu of 3.5 for DOODA can be achieved at 3.0 mol/L HNO3. The stoichiometries of extracted species and extraction thermodynamic parameters were also presented.

For separating americium from lanthanides, a macroporous silica-based polymeric adsorbent (HDEHP/SiO2-P) was prepared in this study. Using this adsorbent, the adsorption characteristics of 241Am(III) and lanthanides were investigated in HNO3 solutions. The obtained results displayed that heavy lanthanides had greater adsorption towards HDEHP/SiO2-P than Ce(III) and 241Am(III). The adsorption behavior of 241Am(III) was found to be similar with Ce(III) in 0.1–0.3 M HNO3 solutions. The adsorption kinetics of Gd(III) and Ce(III) reached equilibrium within 2 h and fitted well with the pseudo-second-order kinetic model.

Solvents on the base of diamides of heterocyclic dicarboxylic acids are promising alternatives for studied Grouped ActiNide EXtraction (GANEX) solvents. Advantage of these ligands is the possibility of simultaneous extraction not only of residual uranium and plutonium, but also minor actinides—neptunium, americium and curium. Two flowsheets on the base of diamides of heterocyclic dicarboxylic acids for separation of actinides form acidic solutions were developed, tested in laboratory scale and compared. Both flowsheets allow separation of more than 99.95% of actinides from raffinates with high content of lanthanides.

Mass spectrometric analysis of 241Am is advantageous from the point of view of its quick analysis ability and low detection of limit. To accurately determine 241Am by mass spectrometry, interfering elements (IEs) including Bi, Hf, Hg, Pb, Pt, Pu and Tl need to be removed during the sample preparation. The extraction behaviors of IEs in HNO3 and HCl mediums were systematically studied, for the commonly employed extraction resins in 241Am studies (TRU, DGA-N and DGA-B). Based on the results, a chemical separation procedure was proposed for each investigated resin to remove IEs from the Am fraction prior to mass spectrometric determination. Standard reference material IAEA-soil-6 was used to evaluate the proposed procedures. The results showed that the IEs in were completely removed and 241Am was accurately determined for all proposed procedures in coupling with the proper co-precipitation method. The decontamination factors (DFs) of Pu in the procedures were on the order of 102, after one calcium co-precipitation was incorporated to remove the majority of the matrix elements before Am and IEs separation, and that was sufficient for the analysis of global fallout sourced 241Am samples. DFs (Pu) up to 103 could be obtained when double calcium co-precipitations were employed, demonstrating the ability of the proposed procedures to analyze Fukushima Daiichi Nuclear Power Plant accident sourced 241Am in environmental samples.

The radiation stability of N,N-di-alkyl-2-hydroxyacetamide derivatives having alkyl side chain varying from hexyl to decyl was studied as a function of absorbed dose of gamma irradiation up to 700 kGy. The samples were irradiated as neat, and as 0.2 M solutions in n-dodecane in the presence and absence of 4 M nitric acid. The radiolytic degradation of the compounds were assessed by the measurement of distribution ratio of Am(III) (DAm(III)) and also by the measurement of hydrodynamic properties such as density, viscosity and phase disengagement time.

Kinetics of 152Eu and 241Am extraction by nitrogen-bearing alkyl amino phenol oligomer YaRB and tert-butylthiacalix[4]arene TCA from carbonate-alkaline media was studied. Both extractants efficiently extract americium and europium in pH interval 12–14. The maximum of americium extraction is located at the lower values of pH, compared with europium. YaRB extracts americium and europium faster than TCA, and at the same time, americium is extracted faster than europium by both extractants. In general, thiacalixarene TCA is regarded as more efficient extractant than alkyl amino phenol oligomer YaRB.

152Eu and 241Am recovery from HNO3 by conventional and micelle mediated extraction are studied. It is stated that radionuclides distribution ratios D (K D) in micelle mediated extraction are significantly higher than those of conventional extraction, with 241Am is slightly less extracted than 152Eu. Distribution ratios dependence on medium acidity is similar for both processes, with extraction maximum at C (HNO3) = 0.2–1 mol L−1. Microscopic research and dynamic light scattering prove micellar nature of calixarene solutions. Nano-scale of particles, which accumulate radionuclides, is confirmed by ultramicrofiltration. This method is also applied for studies of radionuclides re-extraction and electrochemical deposition.

The aim of this work is to present the method for sequential plutonium and americium activity determination in air filters using chromatographic radionuclide separation and alpha spectrometry measurement. The developed method may be employed for the purposes of workplace monitoring and as an indicator of the need of introducing the individual monitoring as well as a useful complementation of individual monitoring. Basic parameters describing the developed method such as values of chemical recoveries and minimum detectable activities for plutonium and americium isotopes have been determined. Applied counting efficiency was obtained using Monte Carlo calculation method.

In this study, a certified plutonium metal reference material (CRM 126) with a known production history is examined using analytical methods that are commonly employed in nuclear forensics for provenancing and attribution. The measured plutonium isotopic composition and actinide assay are consistent with values reported on the reference material certificate. Model ages from U/Pu and Am/Pu chronometers agree with the documented production timeline. The results confirm the utility of these analytical methods and highlight the importance of a holistic approach for forensic study of unknown materials.

The paper describes the effectiveness of uranium(VI) and europium(III) removal from aqueous solutions using potassium ferrate(VI) at different pH values. The removal of a mixture of alpha- and beta-emitting radionuclides (137Cs(I), 90Sr(II), 152Eu(III), 243Am(III), 239Pu(IV), 237+239Np(V), 238+233U(VI)) from synthetic fresh water and simulated seawater has been checked as well. There is an indication that potassium ferrate(VI) could be used as an effective scavenger for almost all investigated radionuclides except cesium.

Two chromatographic extraction materials (DGA resin cartridges and TRU resin columns) for the determination of americium and curium in urine and faeces have been employed in this paper with two different procedures. 243Am tracer has been successfully used as internal standard not only for americium but also for curium with both the chromatographic extractants. In addition, the sequential determination of plutonium and americium/curium isotopes has been tested and the differences between the two methods are presented. The mean values of radiochemical yields, the reproducibility and the minimum detectable activities have been measured and the accuracy tested by PROCORAD© intercomparison exercises.

International audience; A new protocol designed for the rapid determination of U, Th, Pu, Np, Am and Sr in up to 500 mL of river water samples has been developed. The new method employs chromatographic separation, using TEVA, TRU and Sr resins, coupled to an inductively coupled plasma mass spectrometry and to a gas proportional counting (GPC). Excellent figures of merit characterized by recoveries and accuracies exceeding 80 and 90 %, respectively and detection limits below emergency thresholds are obtained. The new GPC methodology for the quantification of radiostrontium led to accurate results even with activity ratios (A89Sr/A90Sr) as high as 95. © 2016, Akadémiai Kiadó, Budapest, Hungary.

A new procedure was developed for the separation of uranium, thorium, plutonium, neptunium and americium based on extraction chromatography using the N,N,N′,N′-tetraoctyldiglycolamide sorbed onto Amberchrom CG-71 (available as DGA resin® from Triskem International). Radioactive waste samples were wet ashed, actinides were preconcentrated by coprecipitation with ferrous hydroxide. The dissolved precipitate was loaded from a reductive media on the column and the actinides were sequentially eluted changing the nature and the acidity of the eluents, the oxidation states of the given actinides, the concentration of the complexing agent, and the temperature. Alpha sources were prepared by micro-coprecipitation from the strip solutions without further processing. High recoveries and decontamination factors were obtained in each alpha source.

The speciation of pentavalent and hexavalent americium (Am) complexes in nitric acid have been studied by X-ray absorption fine structure spectroscopy, UV–visible spectroscopy, and density functional theory. Calculated bond distances for the Am(VI) complex are in reasonable agreement with EXAFS data and suggest the presence of a mixture of AmO2 + and AmO2 2+ as well as a slightly higher kinetic stability for Am(VI) compared to Am(V).

Borosilicate glasses are intended to be the barrier in between the high level nuclear waste and the geosphere. The oxidation state and the coordination geometry of a particular element in the glass influences its solubility, migration and complexation behavior, which in turn influences its long term leaching behavior. In this context, uranium and americium containing barium borosilicate glasses were prepared by sol–gel route and the speciation studies of U and Am in the glasses were carried out using photoluminescence lifetime spectroscopic technique. It was observed that in the matrix the uranium is stabilised as (UO6)6– and the americium as Am3+.

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

An engineering-scale centrifugal contactor test bed was built at Idaho National Laboratory to perform solvent extraction testing for the partitioning of hexavalent americium. The raffinate simulant feed was spiked with 243Am and 139Ce and treated with sodium bismuthate to oxidize americium to Am(VI), filtered and contacted with 1 M DAAP/dodecane using centrifugal contactors. Extraction efficiency comparable to batch contacts was obtained, indicating for the first time that Am(VI) can be maintained under process conditions. Contrary to expectations, stripping was not as effective as expected. However, this result may actually be advantageous to process design, since a scrub step, previously thought to be impossible due to rapid Am(VI) reduction, may now be considered for future flowsheet tests.