Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7963358 | Journal of Nuclear Materials | 2018 | 10 Pages |
Abstract
Melt processing of multi-phase ceramic waste forms offers potential advantages over traditional solid-state synthesis methods given both the prevalence of melters currently in use and the ability to reduce the possibility of airborne radionuclide contamination. In this work, multi-phase ceramics with a targeted hollandite composition of Ba1.0Cs0.3Cr1.0Al0.3Fe1.0Ti5.7O16 were fabricated by melt processing at 1675â¯Â°C and hot isostatic pressing (HIP) at 1250 and 1300â¯Â°C. X-ray diffraction analysis (XRD) confirmed hollandite as the major phase in all specimens. Zirconolite/pyrochlore peaks and weaker perovskite reflections were observed after melt processing, while HIP samples displayed prominent perovskite peaks and low-intensity zirconolite reflections. Melt processing produced specimens with large (>50â¯Î¼m) well-defined hollandite grains, while HIP yielded samples with a more fine-grained morphology. Elemental analysis showed “islands” rich in Cs and Ti across the surface of the 1300â¯Â°C HIP sample, suggesting partial melting and partitioning of Cs into multiple phases. Photoemission data revealed multiple Cs 3d spin-orbit pairs for the HIP samples, with the lower binding energy doublets likely corresponding to Cs located in more leachable phases. Among all specimens examined, the melt-processed sample exhibited the lowest fractional release rates for Rb and Cs. However, the retention of Sr and Mo was greater in the HIP specimens.
Related Topics
Physical Sciences and Engineering
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Nuclear Energy and Engineering
Authors
Christopher S. Dandeneau, Tao Hong, Kyle S. Brinkman, Eric R. Vance, Jake W. Amoroso,