Title: NUSIMEP-7: Uranium isotope amount ratios in uranium particles
Publisher: Publications Office of the European Union
Publication Year: 2011
JRC N°: JRC68421
ISBN: 978-92-79-22794-3
ISSN: 1831-9424
Other Identifiers: EUR 25179 EN
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC68421
DOI: 10.2787/57332
Type: EUR - Scientific and Technical Research Reports
Abstract: The Additional Protocol (AP) authorizes safeguards authorities to verify the absence of undeclared nuclear activities in all parts of a state’s nuclear fuel cycle as well as any other location where nuclear material is or may be present. As part of the Additional Protocol, environmental sampling has become an important tool for the detection of non-declared nuclear activities. In environmental sampling micrometer-sized uranium particles with an isotopic composition characteristic for the processes at the inspected facility need to be collected, identified and analysed. Considering the potential consequences of the analyses, these measurements need to be subjected to a rigorous quality management system. NUSIMEP-7 focused on measurements of uranium isotope amount ratios in uranium particles aiming to support laboratories involved in uranium particle analysis. It was the second NUSIMEP on particle analysis coordinated by IRMM. NUSIMEP-7 was open for participation to all laboratories in the field of particle analysis, particularly also to the IAEA network of analytical laboratories for environmental sampling (NWAL). The NUSIMEP test samples were prepared by controlled hydrolysis of well certified uranium hexafluoride. Participating laboratories in NUSIMEP-7 received the test samples of uranium particles on two graphite disks with undisclosed isotope amount ratio values n(234U)/n(238U), n(235U)/n(238U) and n(236U)/n(238U). The uranium isotope amount ratios had to be measured using their routine analytical procedures. Measurement of the major ratio n(235U)/n(238U) was obligatory; measurement of the minor ratios n(234U)/n(238U) and n(236U)/n(238U) were optional. 24 institutes registered for NUSIMEP-7, whereof 17 have reported measurement results using different analytical methods, among those were 7 NWAL laboratories. The participants’ measurement results have been evaluated against the certified reference values in compliance with ISO 13528:2005. The results of NUSIMEP-7 confirm the capability of laboratories in measuring n(234U)/n(238U), n(235U)/n(238U) and n(236U)/n(238U) in uranium particles of <1 µm. Furthermore they underpin the recent advances in instrumental techniques in the field of particle analysis. In addition feedback from the measurement communities from nuclear safeguards, nuclear security and earth sciences was collected in view of identifying future needs for NUSIMEP interlaboratory comparisons.
JRC Directorate:Health, Consumers and Reference Materials

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