Compositional development of a plutonium surrogate glass without listed RCRA elements (lead and barium)

Meaker, T.F.

doi:10.2172/518762

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Efforts were successful in removing the RCRA metals and the initial composition Lanthanide Borosilicate (LaBS) composition was developed. 5 This glass was later denoted as the LaBS Frit A composition. To prove the technical and economic feasibility of dispositioning excess weapons usable materials with the LaBS Frit A composition, it was necessary to demonstrate that PuO 2 feedstock could be readily incorporated into glass in sufficient quantities.…”

Section: Previous Actinide Glass Formulation Developmentmentioning

confidence: 99%

Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium

Marra¹

2006

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Revision 0iii EXECUTIVE SUMMARYThe Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is a leading candidate for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (La 2 O 3 -B 2 O 3 -SiO 2 (LaBS)) -Frit B) was developed and testing with the LaBS Frit B composition is underway to provide data to support the Yucca Mountain License Application process. The objective of this task was to investigate alternative frit compositions and/or processing conditions that may improve the performance of the reference Frit B -LaBS glass in the repository. The current LaBS Frit B composition was used as the baseline for alternative glass formulation development efforts. A review of the literature and past high actinide concentration glass development efforts was conducted to formulate candidate compositions for testing. Glass science principles were also utilized to determine candidate frit components that may meet task objectives. Additionally, glass processing methods (e.g. slow cooling or induced heat treatment) were investigated as potential means to improve the glass durability and/or minimize fissile material and neutron absorber separation. Based on these analyses, a series of candidate surrogate glasses were fabricated and analyzed. One composition was then selected for fabrication with PuO 2 and subsequently analyzed.A phase equilibrium approach, developed from the assessment of previous high lanthanide glass formulations, was used to recommend modifications to the SRNL Frit B composition. A specific recommendation to increase Ln 2 O 3 a content with concurrent reduction of Al 2 O 3 and SiO 2 content proved to be successful in improving the melting behavior and component solubility of the glass. This change moved the formulation from a compositional region of potential glass-in-glass phase separation toward a region near a low melting eutectic trough. The resulting LaBS Frit X composition was fabricated and tested.The chemical durability of the LaBS Frit X glass was shown to be equivalent to the reference Frit B composition as measured by the Product Consistency Test (PCT). The Frit X composition demonstrated improved component solubility in surrogate and plutonium testing. This composition also exhibited improved devitrification behavior that could translate to lower glass processing temperatures and minimize any negative impacts on glass pouring.Testing with the LaBS Frit X composition also indicated the potential to intentionally precipitate a PuO 2 -HfO 2 solid solution phase. This could result in a means to dramatically improve the plutonium leach performance in the repository by the formation of a highly insoluble phase with an inherent neutron absorber. Preliminary testing indicated that glass heat treatment could be used to intentionally form this phase...

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Section: Previous Actinide Glass Formulation Developmentmentioning

confidence: 99%

Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium

Marra¹

2006

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Actinide Solubility in Lanthanide Borosilicate Glass for Possible Immobilization and Disposition

et al. 1996

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Immobilization by vitrification is one potential disposition option for a portion of the United States’ excess plutonium inventory. Research has been performed to determine the glass forming region of a frit, plutonium and rare earth system. The frit contains mainly oxides of aluminum, silicon and boron; small amounts of ZrO2 and SrO are also included. The rare earth elements provide a flux to the glass during processing. The rare earths are also added as neutron absorbers (to prohibit criticality) in the final vitreous product.This report will show the compositional region, using Th as a Pu surrogate, that should be targeted in future studies for maximum Pu solubility in the lanthanide borosilicate glass system. Durability data and process variables will also be provided.

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Compositional development of a plutonium surrogate glass without listed RCRA elements (lead and barium)

Cited by 2 publications

References 5 publications

Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium

Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium

Actinide Solubility in Lanthanide Borosilicate Glass for Possible Immobilization and Disposition

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