Fast methods for determination of antropogenic actinides and U/Th-series isotopes in aqueous samples

Rapid and simple methods are applied at the PSI radioanalytical laboratory for determining anthropogenic actinides in waste and nuclear reactor waters (U, Pu, Am, Cm) as well as for analysis of naturally occurring α-emitters in continental river and ground water. Anion exchange chromatography followed by α-spectrometry as well as α/β-LSC is applied for the reactor coolant waters. To avoid α-spectrum interference between 238Pu and 241Am at 5.5 MeV, the Pu-fraction is purified using anion exchange resin. Prior to the separation of the Pu-fraction, all actinides (U, Pu, Am, Cm) are adsorbed batch-wise under stirring onto Actinide Resin® and subsequent decomposition of the reagent. The residue is then re-dissolved in a sulfate buffer solution for electrolytic deposition. In tabular water samples isotopes of Ra and Po are analyzed additionally via sorption onto manganese coated discs (Ra) and deposition on silver discs (Po). For counting times of 1 day and use of 0.1–1 l sample aliquots, detection limits of a few mBq l−1 can be obtained easily.