On the sequential separation and quantification of 237Np, 241Am, thorium, plutonium, and uranium isotopes in environmental and urine samples.

The implementation of the one-pass-through separation technique using two stacked chromatography columns of TEVA - TRU resins for the separation of 237Np, 241Am, thorium, plutonium and uranium from environmental and urine samples was investigated. The sequential separation technique proved to be successful and gave similar results to those obtained when using individual separations. The analysis time was considerably improved. The amount of chemical waste was also reduced by 50% and the use of HClO4 was avoided. The technique of ICP-MS was also investigated as a complementary technique to alpha-spectrometry.

Determination of 210Pb, 210Po, 226Ra, 228Ra and uranium isotopes in drinking water in order to comply with the requirements of the EU 'Drinking Water Directive.

The European Union published in 2013 a new Drinking Water Directive with stricter requirements for measuring natural radioactivity. In order to adhere to this, a method for sequential separation of 210Pb, 210Po, 238U and 234U in drinking water was applied using UTEVA® and Sr resins. Polonium-210, 238U and 234U were quantified using alpha-particle spectrometry and 210Pb using liquid scintillation counting. Radium-226 and 228Ra were determined using 3M Empore Radium RAD Disks, and their quantification was done using a Quantulus™ 1220 liquid scintillation counter.

A performance comparison of nine selected liquid scintillation cocktails.

Sample load capacity, sample compatibility, influence of sample load on (3)H/(14)C counting efficiency, background count rate, figure of merit, quench resistance, and sample stability for nine selected, commercially available, liquid scintillation cocktails are presented in this study. The cocktails tested are Ecoscint A, Insta-Gel Plus, OptiPhase Hisafe 3, OptiPhase Trisafe, Ready Gel, SafeScint 1:1, Ultima Gold, Ultima Gold LLT, and Ultima Gold XR. For the data acquisition a Packard TriCarb Model 1900CA and a Quantulus 1220 liquid scintillation counter is used. All samples are prepared in either 20mL low potassium, borosilicate glass vials or 20mL high density, polyethylene vials. The aim of the full comparison study is to determine a single cocktail that best suits all measurement requirements of the liquid scintillation laboratory at SCK.CEN for the determination of low levels of radioactivity in biological and environmental samples. The results published in this report are intended to help other laboratories in selecting a cocktail fit for their purposes or to set up a similar study.

A multiple window deconvolution technique for measuring low-energy beta activity in samples contaminated with high-energy beta impurities using liquid scintillation spectrometry

An optimised multiple window counting technique, using liquid scintillation counting combined with internal standardisation and spectrum unfolding has been developed for the assessment of low-level, low-energy beta activity in multilabeled samples containing high-energy beta impurities. Distinct spectral contributions are reconstructed for every individual radionuclide and impurity using software deconvolution techniques. The most important advantages of this method are that it does not require setting up quench correction curves and that the exact knowledge of reference activity is not required, thus eliminating two important sources of uncertainty in the final results. The technique has been successfully used on mixtures of 3H, 14C, 63Ni, 99Tc and 60Co over a wide range of quenching and activity ratios.

The measurement of technetium-99 and iodine-129 in waste water from pressurized nuclear-power reactors.

The program for measuring the dispersal presence of contaminating nuclides in waste streams produced by pressurized-water-reactor (PWR) power plants required the establishment of analytical procedures for a number of nuclides. In this report the procedure to assess 99Tc and 129I content in liquid samples using liquid-scintillation counting is presented. 99Tc and 129I are adsorbed on AG 1 X2 ion-exchange resin. 129I is then eluted with NaOCl and further purified by liquid-liquid extraction using carbon tetrachloride and an aqueous solution of sodium thiosulphate. 99Tc is eluted with hot nitric acid (6 M/60 degrees C). If necessary any 60Co present in the sample is separated by liquid-liquid extraction of the cobalt-TTA complex with iso-BuOH. The overall recovery yield is 96.5 +/- 2.5% for 99Tc and 90.1 +/- 6.2% for 129I. Finally beta-activity is measured by liquid-scintillation counting. A limit of detection of 5 Bq/L can thus be obtained for both 99Tc and 129I.