Determination of the isotope composition and content of U and Pu in environmental samples on the ultrasmall level by isotope dilution mass spectrometry

Abstract

A procedure was developed for isolation and determination of the isotope composition and content of U and Pu on the ultrasmall level in environmental samples of technogenic origin, characterized by a small mass (up to 0.l g) and complex macrocomposition. The procedure is based on isotope dilution and mass-spectrometric measurement of the isotope ratios (IDMS). Subnanogram quantities of U and Pu were isolated using a modification of resin bead technique, involving sorption on a limited number of anion exchanger beads and allowing, after desorption, analysis of the solutions containing the selectively isolated nanogram quantities of U or 10 312 310 315 g of Pu. The measurements were carried out on thermal ionization mass spectrometers manufactured in Ukraine and Russia with a modernized ion registration system utilizing a position-sensitive detector based on microchannel plates. Uranium was analyzed by the laser luminescence method suitable for measuring fractions of nanograms of U accurately to within 10%. This procedure, combining highly sensitive methods of isolation of ultrasmall quantities of U and Pu with the mass-spectrometric method of analysis, is applied at the Radium Institute (acting as a national laboratory of IAEA) and at the Institute of Analytical Instrument Designing, Russian Academy of Sciences, in analysis of inspection samples submitted by IAEA for monitoring the activity of nuclear facilities under the Treaty on Nonproliferation of Nuclear Weapons.

Pu(iii) and Cm(iii) in the presence of EDTA: aqueous speciation, redox behavior, and the impact of Ca(ii)

“…21 This reviewed nearly all available literature on the Pu(III)-EDTA system dating back to the late 1950s and analyzed it for selection within the database project based on strict criteria. [28][29][30][31][32][33][34][35][36] From this review process, two Pu(III)-EDTA complexes were selected within the NEA-TDB with log b (Pu(EDTA) À ) ¼ (20.180 AE 0.370) and log b (Pu(HEDTA)(aq)) ¼ (22.020 AE 0.260). Both selected constants were taken from Merciny et al, 32 who utilized potentiometric titrations at pH ¼ 1-9.5 and I ¼ 1 M KCl to investigate the Pu(III)-EDTA system.…”