Valenzstabilisierung von Neptunium in salpetersauren Medien bei der Wiederaufarbeitung abgebrannter Brennelemente
Feldhaus, P. (Corresponding author)
Publikationen vor 2000; PRE-2000; Retrocat
Jülich Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag 1996
110 p.
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Addenda
Berichte des Forschungszentrums Jülich 3309
OpenAccess
OpenAccess
Please use the identifier: http://hdl.handle.net/2128/21749 in citations.


A possibility of standarizing the extraction-behavior of Neptunium during the reprocessing of spent nuclear fuel corresponding to PUREX-Process was investigated. The aim of the work was a quantitative dirigation of the Transuraniumelement (TRUE) into the raffinat of the first extraction cycle by a complete redoxconversion of the Neptunium valence states to unextractable Np(V). In the beginning the theoretical and experimental research focussed on the redoxchemistry of the actinide during the fuel dissolution and the feed preparation. Thereby the nitrous acid, which is produced by a radiological, photochemical and reductive degradation of the nitric acid, revealed an ambivalent influence on the Neptunium valences. By a short-term increase in HNO$_{2}$-concentration the Np(V)-fraction could be obviously risen. The use of some stabilizing reagents inhibited a later reoxidation to Np(VI) also catalyzed by nitrous acid. The urea used for this purpose also led to a further increase in the obtained conversion rates due to a Np(VI)-reduction. The analysis of the valence distribution was performed by an extraction method. This had been compared to chromatographic separation in some preliminary investigations and had tumed out to be comparably reliable and easily manageable.