99Technetium is one of the most abundant, long-lived radiotoxic isotopes in used nuclear fuel (UNF). As such, it is targeted in UNF separation strategies such as UREX +, for isolation and encapsulation in solid waste forms for storage in a nuclear repository. We report here results of a systematic investigation regarding the incorporation of 99Tc into ternary oxides of different structure types: pyrochlore (Ln2Tc2O7), perovskite (SrTcO3), and a spinel derivate (Sr2TcO4). The goal of this study was to determine synthesis conditions to these potential waste forms to immobilize 99Tc and to harvest crystallographic and thermophysical properties. Therefore Rietveld structure analysis was applied to allow a crystallographic description, while thermophysical properties were determined using a physical property measurement system (PPMS). The ternary oxides exhibited good crystallinity and their lattice parameters and atomic coordinates could be refined with high accuracy. Furthermore critical temperatures for superconductivity for the oxides were determined.

Fabrication and properties of Tc-bearing pyrochlores, perovskite- and spinel derivates

243rd National Meeting (2012)

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