Author:
Fortner Jeffrey A.,Kropf A. Jeremy,Finch Robert J.,Cunnane James C.
Abstract
AbstractTechnetium-99 99Tc) is an important radionuclide in repository models owing to its relatively long half-life and the high aqueous solubility of compounds where it is inthe heptavalent state. The vast majority of the 99Tc inventory presently slatedfor disposal is contained in oxide commercial spent nuclear fuel (CSNF), where it is divided (along with its cohort, molybdenum) betweenexsolved, intermetallic “epsilon” particles and isolated, likely oxidized, atoms distributed in the uranium dioxide matrix. We present recent evidence from synchrotron x-ray fluorescence spectroscopy, electron microscopy, and fuel dissolution testing on the likely oxidation state, coordination environment, and physical disposition of technetium and molybdenum in CSNF. Effects of the relative proportioningof technetium and molybdenum among the metallic and oxidized states in CSNF, andtheir distribution in or near grain boundaries and gaps on release during CSNF corrosion testing are discussed.
Publisher
Springer Science and Business Media LLC
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