Comparative study of fission product release of homogeneous and heterogeneous high-burn up MOX fuel by Knudsen Effusion Mass Spectrometry supported by EPMA, SEM/TEM and thermal diffusivity investigations

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Comparison of fluorescence-enhancing reagents and optimization of laser fluorimetric technique for the determination of dissolved uranium

Results from tests aimed at optimizing an instrumental procedure for the direct and fast determination of uranium in solution by laser fluorescence are presented. A comparison of sample fluorescence measured using different fluorescence enhancing reagents was performed: sodium pyrophosphate, orthophosphoric acid, sulphuric acid and a commercially available fluorescence enhancer were tested for the determination of uranium. From the experimental results, 0.01 M Na4P2O7-10H2O showed the best performance. Effects of reagent pH, different matrices, different concentrations of dissolved Th, and sample volume were investigated. Applications of the improved procedure for the determination of uranium in samples arising from UO2-based high level nuclear waste dissolution studies are described. © 2010 Akadémiai Kiadó, Budapest, Hungary.Peer Reviewe

Sorption studies of strontium on carbon nanotubes using the Box-Behnken design

WOS: 000343091300008Adsorption of Sr on multi-walled carbon nanotubes (MWCNTs) was investigated to explore their possible use as an efficient adsorbent for nuclear waste streams. MWCNTs were purified and oxidized with HNO3 prior to testing adsorption. Oxidized MWCNTs were then employed in batch experiments as sorbent of Sr from aqueous solutions. The Box-Behnken experimental design was used to suitably vary the parameters of interest, i.e., temperature, initial Sr2+ concentration, and shaking time. Langmuir, Freundlich and Dubinin-Radushkevich models were applied to fit the adsorption isotherms. The Dubinin-Radushkevich model exhibited the best agreement. Adsorption kinetics was also studied; it was well described by a pseudo-second-order rate model. Adsorption thermodynamics was investigated in the temperature range 293-333 K; the variations of the standard free energy (Delta G degrees), standard enthalpy (Delta H degrees) and standard entropy (Delta S degrees) were obtained. Oxidized MWCNTs show the potential to be a promising candidate for the preconcentration and solidification of Sr from large volumes of aqueous solution

Can carbon nanotubes play a role in the field of nuclear waste management?

WOS: 000263758600007PubMed ID: 1935088

On Uranium Precipitates at the Simulated Near-field Conditions

see attachmentJRC.E.3-Materials researc

Characterization of Alloy Particles Extracted from Spent Nuclear Fuel

We characterized, for the first time, submicro- and nanosized fission product-alloy particles that were extracted nondestructively from spent nuclear fuel, in terms of noble metal (Mo-Ru-Tc-Rh-Pd-Te) composition, atomic level homogeneity and lattice parameters. The evidences obtained in this work contribute to an improved understanding of the redox chemistry of radionuclides in nuclear waste repository environments and, in particular, of the catalytic properties of these unique metal alloy particles