Accurate determination of Curium and Californium isotopic ratios by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) in 248Cm samples for transmutation studies

Abstract

46The French Atomic Energy Commission has carried out several experiments including the 47 mini-INCA (INcineration of Actinides) project for the study of minor-actinide transmutation 48 processes in high intensity thermal neutron fluxes, in view of proposing solutions to reduce 49 the radiotoxicity of long-lived nuclear wastes. In this context, a Cm sample enriched in 248 Cm 50 (~97 %) was irradiated in thermal neutron flux at the High Flux Reactor (HFR) of the Laue-51Langevin Institute (ILL). This work describes a quadrupole ICP-MS (ICP-QMS) analytical 52 procedure for precise and accurate isotopic composition determination of Cm before sample 53 irradiation and of Cm and Cf after sample irradiation. The factors that affect the accuracy and 54 reproducibility of isotopic ratio measurements by ICP-QMS, such as peak centre correction, 55 detector dead time, mass bias, abundance sensitivity and hydrides formation, instrumental 56 background, and memory blank were carefully evaluated and corrected. Uncertainties of the 57 isotopic ratios, taking into account internal precision of isotope ratio measurements, peak 58 tailing, and hydrides formations ranged from 0.3% to 1.3%. This uncertainties range is quite 59 acceptable for the nuclear data to be used in transmutation studies.

On the polymerization of hexavalent uranium. An electrospray mass spectrometry study

“…There is an important discrepancy between model prediction and ESI measurements. The detected (3,4) species fits the prediction of the (3, 5) species, the measured (3, 5) abundance is much lower. Since the dimer is reproduced correctly, a general artifact due to the ESI process such as the addition of protons discussed above seems less likely, though it can not be fully excluded.…”

“…The dominant polymer at pH > 5, however, is the trimer. We found evidence for a geometric stabilization of the (3,5) and (3,4) species in contrast to for instance Zr(IV) or Th(IV) hydrolysis (see below). This phenomenon is also in accordance with expectations from the thermodynamic model.…”

“…The mass spectrum of sample C2 reveals clearly a high abundance of mononuclear and dimeric ions: the doubly charged uranyl ion with and without a nitrate anion (UO 2 ) 2 + and ðUO 2 ÞNO þ 3 (blue) (both (1, 0)), respectively, the mononuclear uranyl hydroxide complex (UO 2 )(OH) + (cyan, (1, 1)) and the dimer, again with and without a nitrate anion ðUO 2 Þ 2 ðOHÞ 2þ 2 and (UO 2 ) 2 (OH) 2 (NO 3 ) + (yellow, both (2, 2)). Dimers with a lower number of hydroxide ligands (magenta (2, 1), white (2, 0)) and trimers ðUO 2 Þ 3 ðOHÞ 2þ 4 , (UO 2 ) 3 (OH) 4 (NO 3 ) + (both green (3,4)) and ðUO 2 Þ 3 ðOHÞ 3 ðNO 3 Þ þ 2 (red, (3, 3)), are less abundant. Though it is tempting to treat the species distribution in the mass spectra as a one-to-one image of the species distribution in solution, some precautions are necessary.…”

“…In recent years mass spectrometric (MS) techniques have been applied in increasing number to investigate questions in the context of the nuclear fuel cycle. [1][2][3][4][5][6][7][8][9] One issue of particular concern is the speciation of radionuclides in solution. On one hand fuel processing depends on dissolution in strong acids and the characteristic species distributions of for instance U or Pu needs to be known.…”

An alternative method for chronometric determinations involving curium

“…14,18 One of the primary contributors to the uncertainty was hydride formation, which they successfully addressed. 14,18 One of the primary contributors to the uncertainty was hydride formation, which they successfully addressed.…”