Development and comparison of high accuracy thermal ionization mass spectrometry methods for uranium isotope ratios determination in nuclear fuel

Abstract

This study presents the development and the comparison of high accuracy methods for uranium isotope determination by thermal ionization mass spectrometry. Two methods for uranium minor isotope ratio determination were compared in term of accuracy, analysable quantity, analysis time and versatility: the total evaporation and the classical method with multi-dynamic sequences. The mathematical correction of the abundance sensitivity and the detector calibration within the classical method helps decreasing the uncertainties and the biases compared to the total evaporation method. This comparative study was conducted within the framework of the "2017 Nuclear Material Round Robin" participation organized by the International Atomic Energy Agency.

Development and comparison of two high accuracy methods for uranium concentration in nuclear fuel: ID-TIMS and K-edge densitometry

“…This solution (pellet + nitric acid) was heated to 135 • C in a PFA vial until complete dissolution. The dissolution solution had about 250 g L -1 uranium concentration [10].…”

“…The measurements were performed using Faraday cups coupled to 10 11 Ω current amplifiers (hereafter referred to as FC 11). All the isotope ratio measurements were performed with the total evaporation method (TE method) described previously [10]. The 238 U + ion beam target intensity was set at 1 V and 2.2 V for the VG Sector 54 and for the Triton TIMS, respectively.…”

“…The present study was performed in the context of the "2017 Nuclear Material Round Robin" organized by the International Atomic Energy Agency (IAEA) which aims at determining the uranium isotope ratio and mass fraction in nuclear materials. The isotope ratios determination was presented in a previous paper [10]. This paper presents a comparison between the ID-TIMS and the K-edge densitometry for the uranium concentration determination with high accuracy in a uranium pellet.…”

“…Thermal-Ionization Mass Spectrometry (TIMS) is the reference technique for the accurate determination of uranium isotope ratios [8][9][10][11][12][13]. The ID methodology coupled to TIMS for the isotope ratio measurements (ID-TIMS) is then a powerful combination for the uranium concentration determination.…”

Nd, Am and Cm isotopic measurements after simultaneous separation in transmutation irradiated samples

“…This study is focused on the Am, Cm and Nd isotope ratios determination. Thermal Ionization Mass Spectrometry (TIMS) is one of the reference techniques for the determination of actinides and lanthanides isotopic composition [3][4][5][6][7] . The main sources of bias for TIMS measurements are the isotope fractionation and isobaric interferences.…”