105 research outputs found
High resolution Magic Angle Spinning Solid State Nuclear Magnetic Resonance Facility for Actinides-bearing compounds
No full textSolid-state Nuclear Magnetic Resonance (NMR) using Magic Angle Spinning (MAS) is a very powerful analytical method as it is sensitive to short-range and atomic scale structure. Moreover, this technique allows the study of amorphous samples, and minor crystalline phases, sometimes beyond detection limits of X-ray diffraction (XRD). In 2007, Ian Farnan, Herman Cho and William J. Weber, at Pacific Northwest National Laboratory (PNNL), caused a stir in the actinide community with their MAS-NMR investigation of a-irradiation damage in natural and 238/239Pu-doped zircons (ZrSiO4). At the Joint Research Centre's (JRC) Institute for Transuranium Elements (ITU), we were immediately enthusiastic about this breakthrough and sought to establish a similar facility in Europe. In this publication, we will give an overview about the new and unique NMR spectrometer with an active glovebox allowing to perform MAS experiments at very high-spinning speed on highly radioactive compounds. Some of the first and very promising results will also be presented.JRC.E.4 - Nuclear fuel
Solid-State 17O Nuclear Magnetic Resonance Spectroscopy Without Isotopic Enrichment: Direct Detection of Bridging Oxygen in Radiation Damaged Zircon
No full textProtocols are presented for obtaining natural abundance O-17 magic angle spinning and static NMR spectra in the solid state. Rotor-assisted population transfer (RAPT), Carr-Purcell-Meiboom-Gill (CPMG) echo trains and cross-polarisation (CP) are all used to obtain spectra of sites with large as well as small electric field gradients in proton and non-proton containing inorganic materials. Spectra are of sufficient quality to obtain the typical NMR parameters by standard fitting of the spectra. The protocol is then applied to identifying the changes that accompany radioactive decay in zircon (ZrSiO4) where enrichment is impossible. The O-17 NMR spectra of a partially metamict zircon sample clearly show evidence of bridging oxygens being produced as a consequence of radiation damage. The spectra have been acquired at moderate magnetic fields over periods typically of 60 h (I weekend) and it is concluded that a 'routine' overnight 110 experiment of 15 h at high field (e.g. 21 T) may well be possible. (C) 2004 Elsevier Inc. All rights reserved.</p
Site populations and short range order in aluminosilicates investigated by 27Al solid-state NMR
No full text29Si and 17O (Q)CPMG-MAS solid-state NMR experiments as an optimum approach for half-integer nuclei having long T1 relaxation times
No full textInvestigation of the maximum dissolution rates and temperature dependence of a simulated UK nuclear waste glass in circum-neutral media at 40 and 90°C in a dynamic system
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