Comparison of structure, morphology, and leach characteristics of multi-phase ceramics produced via melt processing and hot isostatic pressing
- Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
- Clemson Univ., SC (United States)
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia)
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 1675 °C and hot isostatic pressing (HIP) at 1250 and 1300 °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 (>50 μm) 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 1300 °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.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC09-08SR22470
- OSTI ID:
- 1427454
- Alternate ID(s):
- OSTI ID: 1548737
- Report Number(s):
- SRNL-STI-2017-00651; PII: S0022311517314241; TRN: US1802593
- Journal Information:
- Journal of Nuclear Materials, Vol. 502, Issue C; ISSN 0022-3115
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Thermodynamic assessment of the hollandite high‐level radioactive waste form
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journal | April 2019 |
Synthesis and phase structure of (Cs0.8−xBa0.4+x)(Al3+1.6+ xTi4+6.4− x)O16 ceramics using sol-spray pyrolysis route for immobilizing radioactive cesium
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journal | May 2019 |
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