Determination of zirconium isotope composition and concentration for nuclear sample analysis using Thermal Ionization Mass Spectrometry

Abstract

A new Thermal Ionization Mass Spectrometer (TIMS) analytical procedure was developed to measure with high accuracy the zirconium isotope abundance and concentration without molybdenum correction in nuclear samples. A zirconium selective separation using UTEVA column was used before the TIMS measurement in order to remove all possible isobaric interferences (Mo, Y, Nb and Ru) in the solution. The separated solution was then deposited onto a filament previously outgassed for 4 hours to reduce the molybdenum traces in the filament. Then, the filament was introduced into the TIMS source and was maintained for 4 hours at a current of 5 A (ionization filament) and 1.2 A (evaporation filament) in order to eliminate all molybdenum trace present in the filament and in the sample. This methodology allowed the zirconium isotope abundance determination without using the molybdenum interference correction equation. The analytical results obtained with a natural solution after separation is in good accordance with the reference values: bias lower than 0.16 % for the 90 Zr, 91 Zr, 92 Zr and 94 Zr isotope abundance, and a bias of ~0.8 % for the minor isotope (96 Zr) were observed. This zirconium abundance determination methodology was used on three nuclear samples. Then, the calibration of a 91 Zr spike solution was performed by reverse isotope dilution using a SPEX standard zirconium solution. The zirconium concentration determination was then performed on the three nuclear samples by isotope dilution using the SPEX standard zirconium solution and the 91 Zr spike solution. The final uncertainties were estimated to be lower than 1 %.

Investigation of the crucial factors affecting accurate measurement of strontium isotope ratios by total evaporation thermal ionization mass spectrometry

“…Theoretically, if the sample loaded on the filament is totally exhausted and the ion currents are integrated, the mass‐dependent bias will be completely avoided, which is the basic concept of total evaporation thermal ionization mass spectrometry (TE‐TIMS), first described by Callis et al By using TE‐TIMS, the repeatability and accuracy of isotopic analysis can be significantly improved without additional internal normalization or external normalization using certified reference materials (CRMs) . Therefore, its applications quickly expanded from U and Pu to other elements such as Ra, Nd, B, Re, Cr, Zr, Eu, Yb, etc. More attractively, with reliable method verification and proper uncertainty evaluation, TE‐TIMS has the potential to be an absolute method for the assignment of certified values of isotopic reference materials.…”

Zr precipitation kinetics in irradiated fuel dissolution solution by TIMS and ICP-MS: a combined study

“…This separation was performed in shielded cell. It was described entirely by Quemet et al [10]. The sample, previously diluted with 8 mol L -1 nitric acid and deionized water in order to obtain a 4 mol L -1 nitric acid matrix, was deposited onto the column.…”

“…Description of filament loading techniques and details on the TIMS Thermo Fischer Triton instrument (Waltham, MA, United States) are given by Quemet et al [10,11]. Concentration analysis by isotope dilution was performed with this developed method [10] while the isotope composition was determined using the classical method.…”

“…When wanting to study Zr precipitation kinetics in nitric acid, many samples are collected for analysis (at least seven, along the course of the reaction). Some analytical techniques are available directly in hot cells such as X-ray Fluorescence (XRF) [8], but in order to determine the zirconium isotope composition and concentration with uncertainties lower than 3%, it is necessary to use either thermo-ionisation mass spectrometry (TIMS) or multi collection inductively coupled plasma mass spectrometry (MC-ICP-MS) [9,10]. The ATALANTE analyses laboratory (L2AT) only owns a nuclearized TIMS in a glove box, needing important dilution factors because of the high level of radiations the samples present.…”

“…The zirconium analysis method by TIMS for nuclear samples was presented by Quemet et al [10], and necessitates to spike the samples in the shielded cell and perform separations before being able to analyse them as after the amount-of substance needed and the uncertainties required are not compatible with important dilution factors. Here, fourteen samples from two different kinetics experiments were supposed to be aliquoted.…”