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Advanced chemical and structural Characterization of Nuclear Waste Materials related to the Nuclear Fuel Cycle

Bahl, Sebastian Peter

Abstract (englisch):

This dissertation reports structural and speciation investigations of simulated and genuine nuclear wastes. Chapters 4 and 5 emphasize on the very first application of the bulk U, Np and Pu M4,5 absorption edge high-energy resolution X-ray absorption near edge structure (HR XANES) method for characterization of U, Np and Pu oxidation states in model and genuine nuclear waste glasses and spent nuclear fuel (SNF). Chapters 6 and 7 address volatilization and precipitation challenges occurring during vitrification of fission products (FP) like Cs, Tc, Ru and Pd. Various approaches are discussed and potential solutions are proposed.
Chapter 4.1 describes the results from the studies of Pu doped borosilicate glasses. Pu(III), Pu(IV) and Pu(VI) are for the first time characterized simultaneously present in a borosilicate glass using Pu M5 edge HR-XANES. It is illustrated that the method can be very efficiently used to determine Pu oxidation states which control the solubility limit of Pu in a glass matrix. HR XANES results show that the addition of excess Si3N4 is not sufficient for complete reduction of Pu to Pu(III) which has a relatively high solubility limit (10-25 wt% PuO2) due to its network-modifying behavior in glasses. ... mehr

Volltext §
DOI: 10.5445/IR/1000075554
Veröffentlicht am 07.11.2017
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Hochschulschrift
Publikationsjahr 2017
Sprache Englisch
Identifikator urn:nbn:de:swb:90-755545
KITopen-ID: 1000075554
HGF-Programm 32.01.04 (POF III, LK 01) Entw.u.Anpassung v.Speziationsmethoden
Verlag Karlsruher Institut für Technologie (KIT)
Umfang XII, 216 S.
Art der Arbeit Dissertation
Fakultät Fakultät für Chemie und Biowissenschaften (CHEM-BIO)
Institut Institut für Nukleare Entsorgung (INE)
Prüfungsdatum 28.04.2017
Schlagwörter HR-XANES, EXAFS, radioactive materials, spent nuclear fuel, nuclear waste glass, nuclear fuel cycle, vitrification, X-ray spectroscopy
Referent/Betreuer Vitova, T.
Geckeis, H.
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