Reprocessing spent nuclear fuel using molten carbonates and subsequent precipitation of rare earth fission products using phosphate / Griffiths Trevor R.,Volkovich Vladimir A.,Yakimov Sergey M.,May Iain,Sharrad Clint A.,Charnock John M. // JOURNAL OF ALLOYS AND COMPOUNDS. - 2006. - V. 418, l. 1-2. - P. 116-121.

ISSN/EISSN:

0925-8388 / нет данных

Type:

Article; Proceedings Paper

Abstract:

Uranium (and plutonium) can be separated from spent fuel by treatment in molten carbonates and air sparging. UO(2) is converted into insoluble uranate species that can be filtered off. The rare earth and other fission product elements remaining in solution can be later precipitated using phosphates as precipitants. A sequence is described that can (in principle) be used to recover and recycle the carbonate melt used. Molten chloride eutectics are more convenient solvents than carbonates for obtaining the detailed chemistry of fission products in molten salts and their selective precipitation as phosphates. We have investigated the behavior of: Cs, Mg, Sr, Ba, lanthanides (La to Dy), Zr, Cr, Mo, Mn, Re (to simulate Tc), Fe, Ru, Ni, Cd, Bi and Te, but here report results for the rare earths. The distribution coefficients of these elements between chloride melts and precipitates were determined. Lithium-free melts favored formation of double phosphates. Rare earth elements and zirconium can be removed from chloride melts but Sr, Ba and Mg are melt cation specific. EXAFS and XANES measurements have established the speciation of both transition and non-transition elements in molten chlorides. EXAFS is largely model dependent, and to ensure the correct coordination number requires absorption spectroscopy data. EXAFS provides the element-Cl distance in the melt, not previously available. At high concentrations, the presence of bridging chlorine atoms can be established by EXAFS. The effect of diluting such melts and preliminary data on the solubilities of rare earth fission product elements in carbonate melts are reported. (c) 2005 Elsevier B.V. All rights reserved.

Author keywords:

reprocessing; molten carbonates; phosphate precipitation; EXAFS; rare earth fission products OXYGEN SOLUBILITY; OXIDATION; UO2; MIXTURES; MELTS; URANATES; POWDER

DOI:

10.1016/j.jallcom.2006.10.060

Web of Science ID:

ISI:000238781500022

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL 20
Note	24th Rare Earth Research Conference, Keystone, CO, JUN 26, 2005
Publisher	ELSEVIER SCIENCE SA
Address	PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Language	English
Keywords-Plus	OXYGEN SOLUBILITY; OXIDATION; UO2; MIXTURES; MELTS; URANATES; POWDER
Research-Areas	Chemistry; Materials Science; Metallurgy \& Metallurgical Engineering
Web-of-Science-Categories	Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy \& Metallurgical Engineering
Author-Email	T.R.Griffiths@chem.leeds.ac.uk
ResearcherID-Numbers	Volkovich, Vladimir/K-8339-2012 Sharrad, Clint/E-2499-2017
ORCID-Numbers	Volkovich, Vladimir/0000-0003-4438-1194 Sharrad, Clint/0000-0001-7372-8666
Number-of-Cited-References	14
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	18
Journal-ISO	J. Alloy. Compd.
Doc-Delivery-Number	060DE