Qualification and initial characterization of a high-purity 233U spike for use in uranium analyses

Abstract

Several high-purity 233 U items from the repository had been rescued and identified for use in uranium isotopic analyses to support a broad variety of applications in nuclear safeguards, nonproliferation, and nuclear forensics. By preserving and maintaining the supply chain of 233 U materials of different pedigree for use as source materials for certified reference materials (CRMs) it is ensured that the safeguards community has the tools needed for high quality analytical measurements of uranium elemental and isotopic amount contents by mass spectrometry. One of the items identified as a source material for a high-purity CRM had been characterized for the uranium isotope-amount ratios using thermal ionization mass spectrometry (TIMS). Additional verification measurements on this material using quadrupole inductively coupled plasma mass spectrometry (ICPMS) had also been performed. The comparison of the ICPMS uranium isotope-amount ratios with the TIMS data, with much smaller uncertainties, provided validation of the mass spectrometric measurement practices using the ICPMS instrument. ICPMS is the measurement method proposed to be used for the initial screening of the purity of all items in the rescue campaign.

Thermal ionisation mass spectrometry (TIMS) in nuclear science and technology – a review

“…A modied total evaporation (MTE) method was, therefore, developed which involves the interruption of the total evaporation process regularly to allow for correction due to background from peak tailing. [54][55][56][57][58] This interruption is also used to check for peak centring as well as ion-beam re-focusing due to the increased sample lament temperature. These modications have signicantly improved the accuracy and measurement uncertainty on the minor isotope abundances.…”

Critical need for plutonium and uranium isotopic standards with lower uncertainties

“…As long as suitable high-purity isotope(s) are available for use as spikes, good quality assay data are obtained by the IDMS method. Qualication and initial characterization of a highpurity 233 U material for use as IDMS spike is described in Mathew et al 48 A novel method for determination of trace amounts of U present in Pu materials is described by Alamelu and Aggarwal. 49…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and functional materials

“…Several high purity 233 U materials that were potentially useful as ID standards for safeguards and nuclear forensics applications were rescued from downblending. 162 The materials were analysed for the U isotope amount ratios ( 233 U/ 238 U, 234 U/ 238 U, 235 U/ 238 U and 236 U/ 238 U) using total evaporation-TIMS. Standard quadrupole-based ICP-MS was used for extra verication.…”

“…The same precision measurements obtained using LRS were better by at least an order of magnitude, with a value of 0.3% being typical. In addition, the 162 Er/ 166 Er could also be determined, which was impossible using PBP. According to the authors, the method enabled fast screening, had sensitive detection, enabled isotopic identication, employed a simple sample preparation thereby reducing contamination and was applicable to particles over a large size range.…”