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2011-Sustainable Industrial Processing Summit
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| Editors: | Florian K |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2012 |
| Pages: | 630 pages |
| ISBN: | 978-0-9879917-2-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Application Of Absorption Spectroscopy For Studying Behaviour Of Radioactive Elements In Molten Salts
Vladimir Volkovich1; Trevor Griffiths2;1URAL FEDERAL UNIVERSITY, Ekaterinburg, Russia; 2REDSTON TREVOR CONSULTING LTD, Leeds, United Kingdom;
Type of Paper: Regular
Id Paper: 133
Topic: 6
Abstract:
High temperature alkali metal chloride-based melts are prospective media for non-aqueous pyrochemical processing of fresh and reprocessing of spent nuclear fuels. Knowing and understanding the behaviour and properties of the spent fuel constituent elements is important for developing feasible technological process. Of all the elements of interest radioactive ones, for obvious reasons, are the least studied. Spectroscopic techniques, especially applied in situ, offer a valuable tool for determining speciation and studying the reactions taking place in molten salt media. Combining spectroscopy with electrochemistry provides even deeper inside into the properties of studied systems. In the present work electronic absorption spectroscopy was applied for studying the behaviour of uranium species containing the metal in the oxidation states +3, +4, +5 and +6 that were formed in a variety of reactions including anodic dissolution of uranium, chlorination of the metal and its oxides, chemical and electrochemical oxidation and reduction of uranium ions. Experimental conditions, such as temperature or even cationic composition of the solvent melt, often influence the outcome of the reactions taking place. An example of this is the reaction of uranium dioxide with hydrogen chloride that depending on temperature and chosen solvent can lead to the formation of U(IV) or U(V) species.Technetium is one of the least studied d-metals. The reactions of technetium metal and its dioxide were studied in fused alkali chlorides by spectroscopic and spectroelectrochemical techniques. The behaviour of technetium is compared with that of rhenium, the element often employed in experimental studies as a stable substitute for technetium.For uranium and technetium the information obtained from the EAS measurements is compared with the results of X-ray absorption spectroscopy experiments performed with molten and quenched chloride salts.