Separation and preconcentration of actinides from concentrated nitric acid by extraction chromatography in microsystems.

An original method of monolith impregnation in microsystem for the analysis of radionuclides in nitric acid is reported. Three microcolumns made of monolith poly(AMA-co-EDMA) were impregnated in COC microsystems. The robustness of the microsystems in nitric acid media until 8 M was demonstrated. High exchange capacity and affinity for tetravalent and hexavalent actinides in concentrated nitric media were obtained. The retention characteristics of the microcolumns impregnated by TBP, TBP-CMPO and DAAP were compared with those of the equivalent commercial particulate resins TBP™, TRU™ and UTEVA™ respectively. The separation of U, Th and Eu was validated in a classical microsystem and a procedure is proposed in a centrifugal microsystem.

Photochemical Synthesis and Versatile Functionalization Method of a Robust Porous Poly(ethylene glycol methacrylate-co-allyl methacrylate) Monolith Dedicated to Radiochemical Separation in a Centrifugal Microfluidic Platform.

The use of a centrifugal microfluidic platform is an alternative to classical chromatographic procedures for radiochemistry. An ion-exchange support with respect to the in situ light-addressable process of elaboration is specifically designed to be incorporated as a radiochemical sample preparation module in centrifugal microsystem devices. This paper presents a systematic study of the synthesis of the polymeric porous monolith poly(ethylene glycol methacrylate-co-allyl methacrylate) used as a solid-phase support and the versatile and robust photografting process of the monolith based on thiol-ene click chemistry. The polymerization reaction is investigated, varying the formulation of the polymerisable mixture. The robustness of the stationary phase was tested in concentrated nitric acid. Thanks to their unique "easy-to-use" features, centrifugal microfluidic platforms are potential successful candidates for the downscaling of chromatographic separation of radioactive samples (automation, multiplexing, easy integration in glove-boxes environment, and low cost of maintenance).

Analysis of twenty five impurities in uranium matrix by ICP-MS with iron measurement optimized by using reaction collision cell, cold plasma or medium resolution.

An analytical procedure was developed to determine the concentration of 25 impurities (Li, Be, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, Ag, Cd, In, Sm, Eu, Gd, Dy, W, Pb, Bi and Th) in a uranium matrix using the quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). The dissolution of U(3)O(8) powder was made with a mixture of hydrochloric acid and nitric acid. Then, a selective separation of uranium using the UTEVA column was used before measurement by Q-ICP-MS. The procedure developed was verified using the Certified Reference Material "Morille". The analytical results agree well except for 5 elements where values are underestimated (Li, Be, In, Pb and Bi). Among the list of impurities, iron was particularly investigated because it is well known that this element possesses a polyatomic interference that increases the detection limit. A comparison between iron detection limits obtained with different methods was performed. Iron polyatomic interference was at least reduced, or at best entirely resolved in some cases, by using the cold plasma or the collision/reaction cell with several gases (He, NH(3) and CH(4)). High-resolution ICP-MS was used to compare the results obtained. A detection limit as low as 8 ng L(-1) was achieved.

A new approach to determine 147Pm in irradiated fuel solutions.

Developments carried out in the Laboratory of Isotopic, Nuclear and Elementary Analyses in order to quantify (147)Pm in spent nuclear fuels analyzed at the CEA within the framework of the Burn Up Credit research program for neutronic code validation are presented here. This determination is essential for safety-criticality studies. The quantity and the nature of the radionuclides in irradiated fuel solutions force us to separate the elements of interest before measuring their isotopic content by mass spectrometry. The main objective of this study is to modify the separation protocol used in our laboratory in order to recover and to measure the (147)Pm at the same time as the other lanthanides and actinides determined by mass spectrometry. A very complete study on synthetic solution (containing or not (147)Pm) was undertaken in order to determine the yield of the various stages of separation carried out before obtaining the isolated Pm fraction from the whole of the elements present in the spent fuel solutions. With the lack of natural tracer to carry out the measurement with the isotope dilution technique, the great number of isotopes in fuel, the originality of this work rests on the use of another present lanthanide in fuel to define the output of separation. The yields were measured at the conclusion of each stage of separation with two others lanthanides in order to show that one of them could be used as a tracer to correct the measurement of the (147)Pm with the separation yield. The total yield (at the conclusion of the two stages of separation) was measured at the same time by ICP-MS and liquid scintillation. This last determination made it possible to validate the use of the (147)Sm (natural) to measure the (147)Pm in ICP-MS since the outputs determined in liquid scintillation and ICP-MS (starting from the radioactive decrease of the source having been used to make the synthetic solution) were equivalent. It is the first time that such measurement is performed in ICP-MS. The measurement of the (147)Pm was finally taken on fuels UOx and MOx by using the (153)Eu like a tracer of the separation yield. The results obtained are in very good agreement with those obtained from neutronic calculation code.

Influence of instrumental parameters on the kinetic energy of ions and plasma temperature for a hexapole collision/reaction-cell-based inductively coupled plasma quadrupole mass spectrometer.

Inductively coupled plasma mass spectrometry (ICP-MS) is widely used in inorganic analytical chemistry for element and/or isotope ratio measurements. The presence of interferences, which is one of the main limitations of this method, has been addressed in recent years with the introduction of collision/reaction cell devices on ICP-MS apparatus. The study of ion-molecule reactions in the gas phase then became of great importance for the development of new analytical strategies. Knowing the kinetic energy and the electronic states of the ions prior to their entrance into the cell, i.e., just before they react, thereby constitutes crucial information for the interpretation of the observed reactivities. Such studies on an ICP-MS commonly used for routine analyses require the determination of the influence of different instrumental parameters on the energy of the ions and on the plasma temperature from where ions are sampled. The kinetic energy of ions prior to their entrance into the cell has been connected to the voltage applied to the hexapole according to a linear relationship determined from measurements of ion energy losses due to collisions with neutral gas molecules. The effects of the plasma forward power, sampling depth, and the addition of a torch shield to the ICP source were then examined. A decrease of the plasma potential due to the torch shielding, already mentioned in the literature, has been quantified in this study at about 3 V.

Analysis by laser-induced breakdown spectroscopy of complex solids, liquids, and powders with an echelle spectrometer.

One of the most promising approaches to laser-induced breakdown spectroscopy (LIBS) experiments involves the use of an echelle spectrometer coupled with an intensified CCD. Even if drawbacks remain with its use, the echelle spectrometer facilitates a multielemental analysis that is more rapid than can be obtained with the more-conventional Czerny-Turner spectrometer and, moreover, does not sacrifice reliability. Quantitative results obtained with such apparatus for solids, liquids, powders, and gases are described and when possible compared with results from Czerny-Turner spectrometers. Liquid analysis by LIBS with echelle spectrometers has allowed a spectral database to be compiled. Once the qualitative spectra of pure elements in aqueous solutions, are obtained, they can be used for qualitative analysis of unknown samples.