Author:
Fabian M.,Gergely F.,Osan J.,Cendak T.,Kesari S.,Rao R.
Abstract
AbstractHigh level radioactive actinides are produced as a side product in reprocessing spent nuclear fuel, for which safe long-term-inert immobilizer matrices are needed. Borosilicate glasses are of great potential amongst the candidates of suitable inert materials for radioactive waste immobilization. Understanding the effects of actinide addition to a borosilicate glass matrix is of great importance in view of waste immobilization. Here we present structural studies of a simplified glass-matrix, − 55SiO2·10B2O3·25Na2O·5BaO·5ZrO2 - upon adding lanthanide (Ln-)oxides: CeO2, Nd2O3, Eu2O3, in two different concentrations 10% and 30w% each, to investigate the effects of lanthanides (Ln) taken as chemical surrogates for actinides. Neutron diffraction combined with of Reverse Monte Carlo simulations show that all investigated glass structures comprise tetrahedral SiO4, trigonal BO3 and tetrahedral BO4 units, forming mixed [4]Si-O-[3]B and [4]Si-O-[4]B linkages. 11B Magic Angle Spinning Nuclear Magnetic Resonance is indicative of simultaneous presence of trigonal BO3 and tetrahedral BO4 units, with spectral fractions strongly dependent on the Ln addition. Ln-addition promote the BO3 + O-→[BO4]– isomerization resulting in lower fraction of boron in BO3, as compared to BO4 units. Raman spectra, in full agreement with neutron diffraction, confirm that the basic network structure consists of BO3/trigonal and SiO4/BO4 tetrahedral units. Second neighbour atomic pair correlations reveal Ce, Nd, Eu to be accommodated in both Si and B sites, supporting that the borosilicate-matrix well incorporates Ln-ions and is likely to similarly incorporate actinides, opening a way to radioactive nuclear waste immobilization of this group of elements in a borosilicate glass matrix.
Publisher
Springer Science and Business Media LLC
Reference62 articles.
1. Veliscel-Carolan, J. Separation of actinides from spent nuclear fuel: a review. J. Haz. Mat. 318, 266–281 (2016).
2. Chun, K. S., Kim, S. S. & Kang, C. H. Release of boron and cesium or uranium from simulated borosilicate waste glasses through a compacted Ca-bentonite layer. J. Nucl. Mat. 298, 150–154 (2001).
3. Jantzen, C. M., Brown, K. G. & Pickett, J. B. Impact of phase separation on durability in phosphate containing borosilicate waste glasses for INEEL. WSRC-MS-2000-00307 (Westinghouse Savannah River Company Report, 2000).
4. Stefanovsky, S. V., Shiryaev, A. A., Zubavitchus, J. V., Veligjanin, A. A. & Marra, J. C. Valence State and Speciation of Uranium Ions in Borosilicate Glasses with a High Iron and Aluminum Content. Glass Phys. Chem. 35, 141–148 (2009).
5. Lopez, C. et al. Solubility of actinide surrogates in nuclear glasses. J. Nucl. Mater 312, 76–80 (2003).
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