TRU Resin Research Articles

Evaluation of alkali fusion and acid leaching methods for the determination of insoluble plutonium and americium in fecal samples

Monitoring of radiation workers of fuel reprocessing plant and fuel fabrication facility for internal contamination is carried out by analyzing their urine and fecal samples. Assessment of intake is made from these results using standard biokinetic and dosimetric models. In the analysis of fecal samples, there is a need for improvement in the pretreatment technique for complete dissolution of the sample. Conventional alkali fusion method has yielded recovery of plutonium in the range of 12–60% with a mean of 36%. Newly adopted acid leaching followed by hydrogen fluoride treatment method achieved recovery in the range of 43 to 90% with a mean of 70%. Conventionally, the separation of and was carried out at Bioassay Lab., Tarapur by alkali fusion followed by the anion exchange separation for Pu and cation exchange separation for Am. This paper deals with an alternative method in which initially the entire ash of the sample spiked with 236Pu tracer (3–11 mBq) and 243Am tracer (2.8–14.5 mBq) was acid leached and Pu was separated by anion exchange method and Am by using TRU resin.

Extraction Behavior of Americium and Curium on Selected Extraction Chromatography Resins from Pure Acidic Matrices

Due to the similar chemical properties between the neighboring trivalent actinide elements americium and curium, their extraction behavior is often perceived as indistinguishable. In this work, the characterization of seven extraction chromatography resins (TEVA, TRU, DGA(N), Actinide, Ln, Ln2, and Ln3) for these trivalent actinides from acidic matrices (HNO3, HCl, and HBr) has provided some evidence to the contrary. In most cases, Am(III) and Cm(III) exhibit identical extraction properties. However, separation is possible with TRU and DGA(N) resins as demonstrated in this study. The extraction shows a strong dependency on the specific anion in solution that follows the order NO3−>Br−>Cl−.

Rapid determination of actinides in seawater samples

A new rapid method for the determination of actinides in seawater samples has been developed at the Savannah River National Laboratory. The actinides can be measured by alpha spectrometry or inductively-coupled plasma mass spectrometry. The new method employs novel pre-concentration steps to collect the actinide isotopes quickly from 80 L or more of seawater. Actinides are co-precipitated using an iron hydroxide co-precipitation step enhanced with Ti+3 reductant, followed by lanthanum fluoride co-precipitation. Stacked TEVA Resin and TRU Resin cartridges are used to rapidly separate Pu, U, and Np isotopes from seawater samples. TEVA Resin and DGA Resin were used to separate and measure Pu, Am and Cm isotopes in seawater volumes up to 80 L. This robust method is ideal for emergency seawater samples following a radiological incident. It can also be used, however, for the routine analysis of seawater samples for oceanographic studies to enhance efficiency and productivity. In contrast, many current methods to determine actinides in seawater can take 1–2 weeks and provide chemical yields of ~30–60 %. This new sample preparation method can be performed in 4–8 h with tracer yields of ~85–95 %. By employing a rapid, robust sample preparation method with high chemical yields, less seawater is needed to achieve lower or comparable detection limits for actinide isotopes with less time and effort.

Rapid determination of actinides in asphalt samples

A new rapid method for the determination of actinides in asphalt samples has been developed that can be used in emergency response situations or for routine analysis. If a radiological dispersive device, improvised nuclear device or a nuclear accident such as the accident at the Fukushima Nuclear Power Plant in March, 2011 occurs, there will be an urgent need for rapid analyses of many different environmental matrices, including asphalt materials, to support dose mitigation and environmental clean-up. The new method for the determination of actinides in asphalt utilizes a rapid furnace step to destroy bitumen and organics present in the asphalt and sodium hydroxide fusion to digest the remaining sample. Sample preconcentration steps are used to collect the actinides and a new stacked TRU Resin + DGA Resin column method is employed to separate the actinide isotopes in the asphalt samples. The TRU Resin plus DGA Resin separation approach, which allows sequential separation of plutonium, uranium, americium and curium isotopes in asphalt samples, can be applied to soil samples as well.

Rapid Column Extraction Method for Uranium in Urine

The conventional method used for estimation of uranium (U) in bioassay samples takes nearly 4–5 days for complete sample analysis. In cases of incidental exposures, there is a need to reduce overall analysis time for the estimation of U in bioassay samples. Therefore, efforts were made in the present study to develop a comparatively rapid method for analysis of U in urine. For this purpose, a known amount of U(natural) standard was added to synthetic urine samples (1 L) and separated from by solid phase extraction chromatography using TRU resin (Eichrom Technologies, Inc.). The radiochemical yield recovery observed for U was 92.6% by this method. As a part of quality assurance, the method standardized in the present study was applied for estimation of U in urine samples collected from members of the public (MOP) and the results were compared to those previously obtained using ion exchange chromatography and fission track analysis (FTA).

A New Method to Analyze 242mAm in Low-Level Radioactive Waste Based on Extraction Chromatography and β-ray Spectrometry

A new method for identifying (242m)Am in low-level radioactive waste (LLW) using β-ray spectrometry is proposed. First, (152)Eu, (241+242m+243)Am, and (244)Cm in a digested solution of simulated LLW were separated from the major components of the digested solution and Pu using a transuranium element resin (TRU resin). Next, Am and Cm were separated from Eu using a tetravalent actinide element resin (TEVA resin). A β-ray spectrum of the fraction containing Am and Cm was recorded and the contribution of (239)Np, which is a daughter nuclide of (243)Am, was subtracted to determine the radioactivity of (242m)Am. Also mutual separation of Am, Cm, and Eu was carried out using a tertiary pyridine resin to determine (242m)Am by analyzing the increase of (242)Cm in the Am fraction just after separation of Am from Cm, which is the traditional method. The isotope ratio of (242m)Am/(241)Am determined by β-ray spectrometry agreed with that obtained by analyzing the traditional method.

Rapid fusion method for determination of actinides in fecal samples

A new rapid fusion method for the determination of actinides in fecal samples has been developed at the Savannah River National Laboratory that can be used for emergency response or routine bioassay analyses. If a radiological dispersive device, improvised nuclear device or nuclear accident occur, there will be an urgent need for rapid analyses of environmental, food and bioassay matrices. If an inhalation event occurs and there is confirmed radionuclide activity present via urine analyses of individuals, fecal analyses will typically be required to determine the soluble/insoluble fraction of actinides present as a result of the event to allow a more reliable estimate of radiological dose. The new method for actinides in fecal samples uses accelerated furnace heating, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with stacked TEVA, TRU and DGA resin cartridges. The rapid fusion method provides rugged digestion of any refractory particles present, essential for reliable analysis of actinides in fecal samples. Alpha spectrometry was used to determine the actinide isotopes, but this method can be adapted for assay by inductively-coupled plasma mass spectrometry for actinide isotopes with longer half-lives that have sufficient mass to allow measurement. The method showed high chemical recoveries and effective removal of interferences. The determination of actinides in fecal samples can be performed in less than 12 h in an emergency with excellent quality for emergency samples. The new method, which is much less tedious and time-consuming than other reported methods, can be used for emergency or routine fecal sample analyses. This enables more timely estimates of radiological dose to be performed that utilize soluble/insoluble actinide ratios.

Tin isotope analysis of cassiterites from Southeastern and Eastern Asia

An analytical technique is presented for isotope analysis of a Sn ore mineral, cassiterite. Hydroiodic acid was used to successfully decompose the cassiterite samples. An extraction chromatographic material, TRU resin was utilized for the chemical purification of Sn. Although it has been confirmed that this purification process causes isotopic fractionation, the effect can be corrected. The purification method was used to investigate natural isotopic variations in Sn in cassiterite from Asian countries (Japan, China, Thailand, and Malaysia), via multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Consequently, isotopic variations as large as 0.77‰ in 124 Sn/ 120 Sn were observed for cassiterite samples from Japan and China. The isotopic fractionations of all the samples were dependent on isotope mass. However, the cause of Sn isotopic variation is yet to be established.

Determination of uranium isotope ratios in human urine by sector field inductively coupled plasma mass spectrometry for use in occupational and biomonitoring studies

Determination of uranium isotopes in urine is critical for distinguishing between exposure to natural and anthropogenic sources of uranium. In biomonitoring, the extremely low levels of total uranium [U] present in urine and the complexity of the urine matrix present challenges to accurate isotope ratio determination. We have validated a method for measurement of 234U/238U, 235U/238U and 236U/238U in small-volume, random urine samples at occupational exposure levels, as well as for measurement of 235U/238U at biomonitoring levels. The method has been developed to detect exposure to mixtures of enriched and depleted uranium (DU) among former workers and nearby residents of the NL Industries factory in Colonie, NY, USA. Validation experiments employing solid phase extraction followed by SF-ICP-MS analysis were performed on base urine spiked with isotopic certified reference materials, isotopically depleted urine quality control materials, and natural uranium urine pools. Our results show that extraction with UTEVA resin yields lower blank levels than with TRU resin, and that double washing of the UTEVA resin columns results in further lowering of the blank. At occupational exposure levels ([U] = 50 ng L−1), 234U/238U, 235U/238U, and 236U/238U can be quantified in 1 mL of urine containing 3% DU with relative precisions (1s) of 10%, 0.4%, and 18%, respectively. For urine containing 75% DU and [U] = 50 ng L−1, the relative precision (1s) of 236U/238U is improved to <3%. At biomonitoring levels ([U] = 5 ng L−1), by increasing the urine volume to 4 mL, 234U/238U and 235U/238U can be quantified with relative precisions (1s) of 19% and 0.5%, respectively, whereas 236U/238U cannot be detected. By further increasing urine volume to 8 mL, comparable levels of isotope ratio precision are possible at [U] as low as 1 ng L−1.

The automation and optimization of solid phase extraction inductively coupled plasma mass spectrometry analysis for the high throughput determination of aqueous levels of U, Th, Np, Pu, and Am

The development of an automated chemical and mechanical sequence is presented for actinide analysis by inductively coupled plasma mass spectrometry (ICP-MS) using a column-based chromatographic system with TRU resin for matrix separation. The approach yields a robust method that allows for simple handling with high sample throughput for use in rapid response scenarios. Nanogram-level studies were carried out using ICP-MS with mono-isotopic spiked samples. Sample throughput was extrapolated to successfully handle over 2000 samples a day. This process includes a manual valency adjustment allowing for direct optimal loading while simultaneously minimizing sample dilution, an automated solid phase extraction platform, and a unique transfer system for flow through from the extraction to the ICP-MS detection platform. Bed volumes, reagent compositions, resin environments as well as volume and flow rates were optimized to increase recovery. Under optimal conditions the average recoveries over the range from 0.1 to 1.0 μg L−1 were 238U 106.3 ± 5.4%, 237Np 100.5 ± 2.3%, 242Pu 94.3 ± 5.2% and 232Th 109.2 ± 4.8%. Using synthetic urine as a complex matrix the recoveries were 238U 96.2 ± 1.6%, 237Np 95.4 ± 1.7%, 242Pu 81 ± 2.4%, 232Th 98.8 ± 1.7% and 241Am 53 ± 3.6% for samples at the 1 μg L−1 level co-eluted with a 0.5 M HCl/0.3 M oxalic acid solution. These high recoveries were obtained while successfully removing 99.999% of monitored matrix ion constituents and minimizing reagent volumes, culminating in the development of a method that allows for rapid onsite handling of a large number of samples while maintaining high recovery and consistency inherent to automation.

Zr and U determination at trace level in simulated deep groundwater by Q ICP-MS using extraction chromatography

In the framework of trace element analysis by Q ICP-MS in a simulated deep Callovo-Oxfordian groundwater, separation procedures based on extraction chromatography were developed to eliminate the high salt contents and to concentrate Zr and U simultaneously. Theoretical and experimental speciation studies showed the importance of adjusting the medium to HNO3/HF (0.5M/0.005M) to guarantee the stability over time of the analytes before removal of the matrix. Two preconcentration methods based on TRU® and TODGA® resins were optimized for the simultaneous isolation of Zr and U prior to Q ICP-MS measurements. Using TRU resin, alkali and alkali earth metals contained in the deep groundwater were removed with 2M HNO3 whereas Zr and U were recovered with a HNO3/NH4HC2O4 (0.02M/0.05M) medium. For the separation protocol based on TODGA resin, alkali and alkali earth metals were eliminated with 3M and 11M HNO3 while Zr and U were simultaneously stripped with a HNO3/HF (0.5M/0.2M) medium. The procedure optimized on TODGA resin was validated with the French AFNOR NF T90-210 standard by studying linearity, limits of quantification (LOQ) and separation yields. The LOQ was determined at 0.008μgL−1 for Zr and U after the separation. Both analytes were recovered quantitatively. Compared to a sample dilution implemented to reduce the matrix effects, the developed preconcentration method allowed improving the sensitivity up to a 20 fold factor for Zr and U measurements at trace level by Q ICP-MS.

Reducing measurement uncertainty in 63Ni measurements in reactor coolant water with high 60Co activities

In methods for quantification of 63Ni, in e.g. reactor coolant water, a chemical separation is required due to 63Ni being a pure beta emitter with limited means of quantification. 60Co, a common radionuclide in reactor coolant water, is not completely separated with the commonly used separation procedure, and it is not resolved from 63Ni in the beta spectrum. The separation method discussed in this work consists of TRU resin (Eichrom) and Ni resin (Eichrom). After running the separation procedure, depending on the initial activity of 60Co, there may still remain enough 60Co to interfere in the measurement of 63Ni. The 60Co interference is corrected for via a gamma spectrometric measurement. This correction may, depending on the 63Ni/60Co ratio, introduce a large contribution to the measurement uncertainty. The aim of this work was to evaluate the possibility to reduce the measurement uncertainty of 63Ni measurements by adding a second Ni separation to the method. Double Ni separations were performed on reactor coolant water having a 60Co activity much higher than the 63Ni activity (63Ni/60Co = 0.01), in order to decrease the radioactivity of 60Co in the sample. The measurement uncertainty of the 63Ni measurement result was reduced by a factor of about three.

Determination of 232Th and 230Th in seawater using a chemical separation procedure and thermal ionization mass spectrometry

A method for the determination of 232Th and 230Th in seawater has been developed by substantial modifications of available techniques mainly used for other matrixes. We use a well calibrated 229Th spike and iron oxyhydroxides as a carrier phase for the precipitation of Th from about 3.5 L filtered seawater. The chemical separation and purification of Th from the Fe carrier comprise three ion chromatography steps including AG 1‐x8 (200–400 mesh, Cl− form), TRU Resin, and UTEVA Resin. The separated Th fraction is loaded with a mixture of graphite/phosphoric acid onto zone‐refined single rhenium filaments. These are analyzed in peak‐jumping mode on a thermal ionization mass spectrometer. Due to the low Th concentration in seawater, the 232Th blank constitute a significant problem for the chemical separation of Th from the seawater matrix and also for the filament loading. By applying a detailed cleaning scheme including a HF‐HCl mixture, the total procedural blank could be substantially reduced to approximately 0.4 pg. This is generally &lt; 1% of a typical 232Th concentration in surface seawater, which ranges from about 0.01 to 1 picomol/kg. The analysis of standards, artificial seawater, and a series of seawater samples obtained from the GEOTRACES intercalibration cruises in 2008 and 2009 demonstrate that this method can yield a precision for 232Th concentration in seawater of about 1% to 2% (2σ) and 230Th concentration of about 2% to 5% (2σ).

Rapid determination of actinides in emergency food samples

A new rapid method for the determination of actinides in food samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for emergency response or routine food samples. If a radiological dispersive device or improvised nuclear device event occurs, there will be a urgent need for rapid analyzes of many different environmental matrices, as well as food samples, to support dose mitigation and protect general populations from radioactivity that may enter the food chain. The recent accident at Fukushima nuclear power plant in March, 2011 reinforces the need to have rapid analyzes for radionuclides in environmental and food samples. The new method to determine actinides in food samples utilizes a furnace ashing step, a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with stacked TEVA, TRU, and DGA resin cartridges. The furnace ashing and rapid fusion steps are performed in relatively inexpensive, reusable zirconium crucibles. Alpha emitters are prepared using rare earth micro precipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. The determination of actinides in food samples can be performed in less than 8 h for 10 g samples with excellent quality for emergency samples using short count times. Larger food samples (100 g) may be processed in 24 h or less. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory actinide particles are effectively digested. This method can be used to meet the derived intervention level guidelines recommended by the U.S. Food and Drug Administrations.

Rapid radiochemical method for determination of actinides in emergency concrete and brick samples

A new rapid method for the determination of actinides in emergency concrete and brick samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations or for routine analysis. If a radiological dispersive device (RDD), Improvised Nuclear Device (IND) or nuclear accident occurs, there will be a urgent need for rapid analyses of many different environmental matrices, including building materials such as concrete and brick, to support dose mitigation and environmental clean-up. The new method for actinides in concrete and brick method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a column separation process with stacked TEVA, TRU and DGA Resin cartridges. Alpha emitters are prepared using rare earth microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. The determination of actinides in concrete and brick sample analysis can be performed in less than 8 h with excellent quality for emergency samples. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory actinide particles are effectively digested.

A selective separation method for 93Zr in radiochemical analysis of low and intermediate level wastes from nuclear power plants

The zirconium isotope 93Zr is a long-lived pure β-particle-emitting radionuclide produced from 235U fission and from neutron activation of the stable isotope 92Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half life, 93Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Measurement of 93Zr is difficult owing to its trace level concentration and its low activity in nuclear wastes and further because its certified standards are not frequently available. A radiochemical procedure based on liquid–liquid extraction with 1-(2-thenoyl)-3,3,3-trifluoroacetone in xylene, ion exchange with Dowex resin and selective extraction using TRU resin has to be carried out in order to separate zirconium from the matrix and to analyze it by liquid scintillation spectrometry technique (LSC). To set up the radiochemical separation procedure for 93Zr, a tracer solution of 95Zr was used in order to follow the behavior of zirconium during the process by γ-ray spectrometry through measurement of the 95Zr. Then, the protocol was applied to low level waste (LLW) and intermediate level waste (ILW) from nuclear power plants. The efficiency detection for 63Ni was used to determination of 93Zr activity in the matrices analyzed. The limit of detection of the 0.05 Bq l−1 was obtained for 63Ni standard solutions by using a sample:cocktail ratio of 3:17 mL for OptiPhase HiSafe 3 cocktail.

Radioanalytical determination of plutonium and americium using ion exchange and extraction chromatography technique in urine

The use of anion exchange chromatography for the separation of Pu and extraction chromatography technique for the separation of Am from urine samples was studied. In the earlier method, Pu separation was carried out by anion exchange chromatography followed by Am separation by cation exchange chromatography. The chemical recovery of Am obtained by cation exchange separation method was inconsistent and low in the range 30-70%. In this study, the average Pu recovery obtained using anion exchange chromatography was 89.2 with standard deviation of 10.4 and the average Am recovery obtained using extraction chromatography with TRU resin was 77.4 with standard deviation of 14.8. Moreover, Am separation could be completed within three hours using the TRU column compared to two days that were required for the cation exchange chromatography.

Rapid separation method for actinides in emergency soil samples

Abstract A new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 g in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4–5 h with excellent quality.

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

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

Analysis of Th, U, Pu, and Am in radioactive metal waste using extraction chromatography

In order to analyze actinide elements in radioactive metal waste, the dissolution and chemical separation conditions were optimized. The surfaces of a type 304 stainless steel plate and of pipe waste sampled from the prototype advanced thermal reactor (Fugen) were dissolved in mixed acid solution (HNO3:HCl:H2O = 1:1:4). The resulting solution was evaporated to dryness and dissolved with 2 mol/dm3 of HNO3 to prepare sample solutions. In order to analyze trivalent actinide elements in the sample solution containing a large amount of Fe(III) (>0.1 g) using TRU resin, the effect of Fe(III) concentration on the recovery of Am(III) and reduction effect of Fe(III) to Fe(II) with ascorbic acid were studied. On the basis of results of this study, chemical separation scheme was constructed and Pu and Am in the sample solutions were separated. Thorium and U in the sample solutions were separated with UTEVA resin. High recoveries for all experimented elements were obtained from the analysis of spiked sample solutions, the effectiveness of the method was confirmed.