Irradiated UAmO2 transmutation discs analyses: from dissolution to isotopic analyses

Abstract

This paper details the different steps for the isotopic determination of UAmO2 discs from analytical irradiation. MARIOS and DIAMINO irradiations were performed in materials testing reactors to study the behaviour of americium bearing blanket samples in regard of heterogeneous recycling in sodium-cooled fast reactor. Six irradiated discs were dissolved in hot cells and were analyzed to determine isotope ratios of uranium, plutonium, americium and neodymium. The ratios were measured combining chemical separations and TIMS analyses. Using the double isotope dilution methodology helps measuring 238 Pu/ 238 U, 241 Am/ 238 U and 148 Nd/ 238 U ratios with uncertainty about a few per mil (k = 2).

An isotope dilution mass spectrometry overview: tips and applications for the measurement of radionuclides

“…Such information can be fed back into areas such as the assessment of fuel performance/ qualication, validation of nuclear codes for criticality or for long-term storage of nuclear waste. 31,38,130,214,215 Crucially, these rely on the low measurement uncertainties ID-MS can provide.…”

“…The choice of the spike isotope for the quanti-cation of Nd formed during ssion is different than for Nd with natural isotopic composition due to their different isotopic compositions. A spike enriched in the 146 Nd isotope can be an alternative to 148 Nd and 150 Nd isotopes 33,38 if the entire Nd vector is to be measured. The amount of spike to be added depends on the concentration in the sample, and to some extent this depends on the laboratory's operating license.…”

“…23 Furthermore, the International Atomic Energy Agency (IAEA) considers ID-MS as one of the most accurate methods in terms of the International Target Values (ITVs) for measurement uncertainties applied on safeguarding nuclear materials. 24,25 TIMS and ICP-MS are the techniques of choice to measure the isotope ratio of most elements, 26 for example radionuclides such as Sr, 27 Cs, [28][29][30] Nd, [31][32][33][34] Th, 35,36 U, 33,[37][38][39][40][41] Pu, 3,33,38,40,[42][43][44][45] Am 7,31,38 and Cm. 31,46 ID-MS is a versatile tool for radionuclide quantity measurement and the "gold standard" for nuclear safeguards.…”