Reduction of Pu(VI) by Fe

The main purpose of this task (part of deliverable D6.1) is to study the immobilization/ remobilization of Pu under simulated near-field condi¬tions: Fe as iron coupon mimic the canister material, and magnetite as the relevant crystalline rock fracture filling Fe(II) minerals found at for example ÄSPÖ Hard Rock Laboratory. In collaboration between ITU and Studsvik, solutions of hexavalent Pu were exposed to iron coupons, either freshly polished Fe(0) or pre-corroded and coated with Fe3O4, under anoxic conditions. Plutonium and Fe concentration in solution as a function of time was monitored by sector field inductive coupled plasma mass spectrometry (SF-ICP-MS) and γ-spectrometry. Plutonium precipitate on the iron phases were characterized by scanning electron microscope coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and α-track analysis. It can be concluded that only 1 % of the added amount of Pu(VI) was reduced by Fe3O4 after a contact time of 4 months. There was no Pu(VI) reduction on the Fe coupons. Considering the small negative DG-values and the small amount of Pu(VI) reduced on the magnetite surface it can be concluded that it is a relatively slow reduction reaction.

CARBOL Paul;  WEGEN Detlef;  WISS Thierry;  JANSSEN Arne;  NICHOLL Adrian;  CREMER Bert;  MALMBECK Rikard;  VAN WINCKEL Stefaan;  APOSTOLIDIS Christos;  ALVAREZ SARANDES LAVANDERA Rafael;  HIMBERT Jerome;  CUI Daqing; 

2013-01-21

KIT Scientific Publishing

JRC69267

978-3-86644-921-3,   

1869-9669,   

http://digbib.ubka.uni-karlsruhe.de/volltexte/1000030358,    https://publications.jrc.ec.europa.eu/repository/handle/JRC69267,   

10.5445/KSP/1000030358,