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Accession Number DE2012-1053795
Title Single Phase Melt Processed Powellite (Ba,Ca)MoO4 for the Immobilization of Mo-Rich Nuclear Waste.
Publication Date Sep 2012
Media Count 33p
Personal Author J. Crum J. Marra J. Reppert K. Brinkman K. Fox M. Tang
Abstract Crystalline and glass composite materials are currently being investigated for the immobilization of combined High Level Waste (HLW) streams resulting from potential commercial fuel reprocessing scenarios. Several of these potential waste streams contain elevated levels of transition metal elements such as molybdenum (Mo). Molybdenum has limited solubility in typical silicate glasses used for nuclear waste immobilization. Under certain chemical and controlled cooling conditions, a powellite (Ba,Ca)MoO4 crystalline structure can be formed by reaction with alkaline earth elements. In this study, single phase BaMoO4 and CaMoO4 were formed from carbonate and oxide precursors demonstrating the viability of Mo incorporation into glass, crystalline or glass composite materials by a melt and crystallization process. X-ray diffraction, photoluminescence, and Raman spectroscopy indicated a long range ordered crystalline structure. In-situ electron irradiation studies indicated that both CaMoO4 and BaMoO4 powellite phases exhibit radiation stability up to 1000 years at anticipated doses with a crystalline to amorphous transition observed after 1 X 1013 Gy. Aqueous durability determined from product consistency tests (PCT) showed low normalized release rates for Ba, Ca, and Mo (<0.05 g/m2).
Keywords Composite materials
High level radioactive wastes
Nuclear wastes
Radiation damage
Radioactive waste processing
Raman spectroscopy
Waste forms
X-ray diffraction

Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 77G - Radioactive Wastes & Radioactivity
Corporate Author Pacific Northwest National Lab., Richland, WA.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1308
Contract Number DE-AC09-08SR22470

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