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Journal of Radioanalytical and Nuclear Chemistry
Authors: Claudia Landstetter, Wolfgang Ringer, Arno Achatz, and Christian Katzlberger

Abstract  

90Sr was measured in environmental samples in Upper Austria in the year 2005. After the nuclear weapon tests the average deposition of 90Sr in Austria amounted to 3.3 kBq/m². In 1986 the average deposition was 0.9 kBq/m² [<cite>1</cite>]. To assess the actual condition in soil, grass and cereals 90Sr was measured in these samples. For all samples oxalate precipitation was conducted and strontium specific columns (Eichrom Industries, Inc.) were used. The calcium concentration in these samples was determined to estimate the amount of resin needed for the preparation. For grass and cereal samples columns were packed with the 100–150 μm resin to gain a lower limit of detection LLD below 2 and below 0.1 Bq/kgdry matter respectively. The prepacked 2 mL columns with particle size 100–150 μm were used for soil (LLD below 2 Bq/kgdry matter). After digestion of soil samples, hydroxide precipitation was used as an additional separation step. The 90Sr was measured by liquid scintillation counting. For quality control reasons, first the initial strontium concentration in the sample was determined then a strontium carrier solution was added and after the separation steps the chemical recovery was determined by ICP-MS. Thus, no radioactive tracer and just a small amount of the measuring solution were needed. The results are presented and discussed. These results will be used as reference for further 90Sr analyses which will be conducted in a 5 year period to detect any radiological impact of the nuclear power plant Temelin on the environment of Austria.

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Abstract  

In this study, 90Sr (540 keVβ ), 129I (150 keVβ ) and the gross beta radioactivity concentrations were determined for the samples of tea as the most leading consumed hot drink in the markets (processed and packaged for sale) in our country. Furthermore, the obtained data were statistically analyzed. For determination of 129I (150 keVβ), 90Sr (540 keVβ) and gross radioactivity concentrations in tea samples, a sensor system consisting of scintillation detector with BP4 probe sensitive to beta radiation and a radiation meter (ST7) configurable for windows at desired power was used.

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Abstract  

An inorganic ion exchanger, quinolinephosphomolybdate has been synthesized and characterized by elemental analysis, infrared (IR) and X-ray diffraction (XRD) spectroscopy. This compound is highly stable toward thermal, chemical and radiation dose. This has been employed in the separation of carrier-free 90Y from its parent 90Sr from an equilibrium mixture. The absorbed daughter was recovered by using 0.0284 mol L−1 ascorbic acid solutions at pH 5.0 as eluting agent.

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Abstract  

A rapid bioassay for 90Sr was developed involving preconcentration of 90Sr/90Y from human urine samples with a cation exchange polymer (poly–acrylamido–methyl–propanesulfonic acid) coated onto magnetic nanoparticles, followed by selective elution of 90Sr (over 90Y) with phosphate for determination by liquid scintillation analysis. The minimum detectable activity for this method (4.9 ± 0.5 Bq/L) is lower than the required sensitivity of 19 Bq/L for 90Sr in human urine samples, as defined in the requirements for radiation emergency bioassay techniques for the public and first responders based on the dose threshold for possible medical attention recommended by the International Commission on Radiological Protection. The relative bias was 9.2%, the relative precision was 3.2%, and the linear dynamic range covered 12–600 Bq/L. This simple and rapid bioassay method is found to be in compliance with the HPS ANSI N13.30 performance criteria for radiobioassay.

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Abstract  

The period of date of death of an elephant can be assessed by analyzing four different radionuclides, 14C, 90Sr, 228Th and 232Th in its ivory. These nuclides are supposed to have variing concentrations at different parts of a tusk. The reason is the procedure of growth which takes place at the butt-site of a tusk. Therefore the site of sampling could have a big influence on the assessed date of death. However, to find out if the position of sampling is important a complete tusk was analyzed regarding the distribution of these nuclides. Results show that the concentration activity of 14C and 228Th varies in different parts of a tusk. The activity concentration of 90Sr is very similar in all analyzed parts. The conclusion is that sampling at the butt of a tusk is recommended for age assessment.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Filip Kužel, Petra Staffová, Irena Špendlíková, Jan John, and Ferdinand Šebesta

Abstract  

Solid extractants containing di-(2-ethylhexyl)phosphoric acid (HDEHP) in the support based on modified polyacrylonitrile (PAN) were studied for the determination of 90Sr by means of measuring the activity of its separated 90Y daughter. In this paper, 152Eu and 133Ba were used as chemical homologues of 90Y and 90Sr. For these radionuclides, dependences of mass distribution coefficients (D g) on the nitric acid concentration were measured for several types of HDEHP-PAN solid extractants. The mechanism of the Eu3+ and Ba2+ ions extraction was confirmed to follow the theoretical two-phase equation for the chelating extractants. Further, the influences of the presence of nitrates, calcium and iron ions on the values of D g(Ba, Eu) were determined concentrating on the possibility of masking the iron ions by the addition of the ascorbic acid. This method was tested on the solution simulating the leachate of ashed green plant sample. The results obtained make the application of solid extractants containing HDEHP in PAN support prospective for 90Sr determination.

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Abstract  

The presence of 89Sr and 90Sr in the biosphere constitutes a biological hazard. There are several analytical methods for the determination of 89Sr and 90Sr. Three analytical methods of various application fields using selective Sr resin for Sr separation and DGA resin for Y separation and measuring techniques, i.e. liquid scintillation spectrometry and Cerenkov counting are discussed in the paper. The calculation techniques are compared in the aspects such as trueness and accuracy of the results and the limit of detection. Uncertainties and detection limits are calculated using the spreadsheet method.

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Abstract  

Based on the encouraging results of our initial efforts to develop a 90Sr accelerator mass spectrometry capability, we have undertaken efforts to enhance our system. By changing some key operating parameters and constructing an optimized detector we were able to improve the discrimination of 90Sr from the isobaric interference 90Zr and reduce our instrumental background by nearly two orders of magnitude. Our current background (4 × 106 atoms, 3 mBq) is comparable to that achievable by decay counting, but is still a factor of ten higher than what is theoretically predicted based on the efficiency of our system. Therefore, future plans include implementation of a time-of-flight system to improve the rejection of 90Zr.

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Abstract  

A methodology for the determination of 90Sr in low- and intermediate-level radioactive wastes from nuclear power plants is presented in this work. It is a part of a methodology developed for the sequential radiochemical separation of radionuclides difficult-to-measure directly by gamma spectrometry in these radioactive wastes. The separation procedure was carried out using precipitation and extraction chromatography with Sr Resin, from Eichrom and the 90Sr was measured by liquid scintillation counting (LSC). Optimum conditions for the pretreatment, separation and LSC measurements were determined using simulated samples, which were prepared using standard solutions and carriers. The procedure showed to be rapid and achieved a good chemical yield, in the range 60–90%, and a detection limit of 6.0 × 10−4 Bq g−1. The method was also tested by participation in a national intercomparison program, with aqueous samples, with good agreement of results.

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Abstract  

Characterization of SuperLig® 620 solid phase extraction resin was performed in order to develop an automated on-line process monitor for 90Sr. The main focus was on strontium separation from barium, with the goal of developing an automated separation process for 90Sr in high-level wastes. High-level waste contains significant 137Cs activity, of which 137mBa is of great concern as an interference to the quantification of strontium. In addition barium, yttrium and plutonium were studied as potential interferences to strontium uptake and detection. A number of complexants were studied in a series of batch Kd experiments, as SuperLig® 620 was not previously known to elute strontium in typical mineral acids. The optimal separation was found using a 2 M nitric acid load solution with a strontium elution step of ~0.49 M ammonium citrate and a barium elution step of ~1.8 M ammonium citrate. 90Sr quantification of Hanford high-level tank waste was performed on a sequential injection analysis microfluidics system coupled to a flow-cell detector. The results of the on-line procedure are compared to standard radiochemical techniques in this paper.

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