Title: Crystallization Study of Rare Earth and Molybdenum Containing Nuclear Waste Glass Ceramics

Abstract

A glass-ceramic waste form is being developed for immobilization of waste streams of alkali (A), alkaline-earth (AE), rare earth (RE), and transition metals generated by transuranic extraction for reprocessing used nuclear fuel. Benefits over an alkali borosilicate waste form are realized by the partitioning of the insoluble fission product fraction into a suite of crystalline phases through controlled cooling, including (AE,A,RE)MoO4 (powellite) and (RE,A,AE)10Si6O26 (oxyapatite). In this study, a simplified 8-oxide system (SiO2-Nd2O3-CaO-Na2O-B2O3-Al2O3-MoO3-ZrO2) was melted then soaked at various temperatures from 1450 to 1150°C and subsequently quenched, in order to obtain snapshots into the phase distribution at these temperatures. For these samples, small angle X-ray and neutron scattering, quantitative X-ray diffraction, electron microscopy, 23Na nuclear magnetic resonance, Nd3+ visible absorption, and temperature dependent viscosity were characterized. In this composition, soak temperatures ~1250°C or below appear necessary to nucleate calcium molybdate phase (~10 – 20 nm in diameter). Further cooling produces oxyapatite and total crystallization increases with lower soak temperatures. Both Na and Nd enter the crystalline phases with lower temperature soak conditions. Slow cooling or long isothermal treatments ~975°C produces significantly higher crystal fractions.

Authors:

McCloy, John S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-7476-7771"

Riley, Brian J.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-7745-6730"

Crum, Jarrod ^[2]; Marcial, José  ^[3];

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• Search DOE PAGES for ORCID "0000-0001-6156-5310"

Reiser, Joelle T.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-2638-1580"

Kruska, Karen  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-7396-5338"

Peterson, Jacob A. ^[2]; Neuville, Daniel R.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-8487-5001"

Patil, Deepak S.  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-7019-9081"

Saleh, Muad  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-1391-2784"

Barnsley, Kristian E. ^[5]; Hanna, John V.  ^[5]

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• Search DOE PAGES for ORCID "0000-0002-0644-3932"

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+ Show Author Affiliations

1. Washington State Univ., Pullman, WA (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
3. Washington State Univ., Pullman, WA (United States)
4. Institut de Physique du Globe de Paris, Paris Cedex (France)
5. Warwick Univ., Coventry (United Kingdom)

Publication Date:

Wed Feb 27 00:00:00 EST 2019

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Washington State Univ., Pullman, WA (United States)

Sponsoring Org.:

USDOE Office of Nuclear Energy (NE)

OSTI Identifier:

1497078

Alternate Identifier(s):

OSTI ID: 1499073; OSTI ID: 1558457; OSTI ID: 1571521

Report Number(s):

PNNL-SA-122002
Journal ID: ISSN 0002-7820

Grant/Contract Number:  

AC05-76RL01830; NE0008431

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the American Ceramic Society

Additional Journal Information:

Journal Volume: 102; Journal Issue: 9; Journal ID: ISSN 0002-7820

Publisher:

American Ceramic Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; glass‐ceramics; nuclear magnetic resonance; nuclear waste; rare earths; X‐ray methods