Title: Preparation and Certification of Large-Sized Dried (LSD) Spike – IRMM-1027s
Publisher: Publications Office of the European Union
Publication Year: 2018
JRC N°: JRC111871
ISBN: 978-92-79-87992-0
ISSN: 1831-9424
Other Identifiers: EUR 29274 EN
OP KJ-NA-29274-EN-N
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC111871
DOI: 10.2760/221796
Type: EUR - Scientific and Technical Research Reports
Abstract: Large-Sized Dried (LSD) spikes are used as a fundamental part of the fissile material control of irradiated nuclear fuel and have been provided on a regular basis to safeguards authorities and industry for more than 10 years. This report describes the preparation and certification of a new batch of LSD spikes. IRMM-1027s is a dried nitrate material in cellulose acetate butyrate (CAB), certified for the mass of uranium and plutonium and the uranium and plutonium isotope amount ratios per unit. The material was produced in compliance with ISO/IEC 17034:2016 and certified in accordance with ISO Guide 35:2006. The certified reference materials uranium metal EC NRM 101, enriched uranium metal NBL CRM 116-A and plutonium metal CETAMA MP2 were used as starting materials to prepare the mother solution. This solution was dispensed into individual units by means of an automated robot system and dried down. A solution of an organic substance, cellulose acetate butyrate (CAB) was dried on the spike material as a stabiliser to retain the dried material at the bottom of the vial. In total 950 units were produced. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. The certified values for the uranium and plutonium isotope amount ratios were obtained from the gravimetric preparation of the mother solution, taking into account the mass, purity and isotopic composition of the starting materials. The certified values for the mass of plutonium and uranium per unit were established by isotope dilution thermal ionisation mass spectrometry (ID-TIMS) on randomly selected units. External verification measurements were performed by isotope dilution mass spectrometry (IDMS) and thermal ionisation mass spectrometry (TIMS) on randomly selected units of IRMM-1027s. Uncertainties of the certified values were estimated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity and to characterisation. The main purpose of this material is for use as a spike isotopic reference material to measure the plutonium and uranium amount content of spent nuclear fuel solutions using IDMS. Each unit contains about 55 mg of uranium with a relative mass fraction m(235U)/m(U) of 19.0 % and 1.7 mg of plutonium with a relative mass fraction m(239Pu)/m(Pu) of 97.8 % as dried nitrates in CAB. The whole amount of sample per unit has to be used for analysis.
JRC Directorate:Nuclear Safety and Security

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