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Title: GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE GLASS FOR PLUTONIUM DISPOSITION

Abstract

The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) in Aiken, SC, 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. The objectives of this present task were to fabricate plutonium-loaded lanthanide borosilicate (LaBS) Frit B glass and perform testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the proposed Federal Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit B composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support glass durability testing via the ASTM Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was characterized with X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. This characterization revealed some crystalline PuO{sub 2} inclusions with disk-like morphology present in the as fabricated, quench-cooled glass. A series of PCTs was conductedmore » at SRNL with varying exposed surface area and test durations. Filtered leachates from these tests were analyzed to determine the dissolved concentrations of key elements. The leachate solutions were also ultrafiltered to quantify colloid formation. Leached solids from select PCTs were examined in an attempt to evaluate the Pu and neutron absorber release behavior from the glass and to investigate formation of alteration phases on the glass surface. A series of PCTs was conducted at 90 C in ASTM Type 1 water to compare the Pu LaBS Frit B glass durability to current requirements for High Level Waste (HLW) glass in a geologic repository. The PCT (7-day static test with powdered glass) results on the Pu-containing LaBS Frit B glass at SA/V of {approx} 2000 m{sup -1} showed that the glass was very durable with an average normalized elemental release value for boron of 0.013 g/m{sup 2}. This boron release value is {approx} 640X lower than normalized boron release from current Environmental Assessment (EA) glass used for repository acceptance. The PCT-B (7, 14, 28 and 56-day, static test with powdered glass) normalized elemental releases were similar to the normalized elemental release values from PCT-A testing, indicating that the LaBS Frit B glass is very durable as measured by the PCT. Normalized plutonium releases were essentially the same within the analytical uncertainty of the ICP-MS methods used to quantify plutonium in the 0.45 {micro}m-filtered leachates and ultra-filtered leachates, indicating that colloidal plutonium species do not form under the PCT conditions used in this study.« less

Authors:
; ;
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
901093
Report Number(s):
WSRC-STI-2007-00079
Journal ID: ISSN 0925-8388; JALCEU; TRN: US0702509
DOE Contract Number:
DE-AC09-96SR18500
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Alloys and Compounds
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; BORON; BOROSILICATE GLASS; COLLOIDS; FABRICATION; GLASS; LEACHATES; MORPHOLOGY; NEUTRON ABSORBERS; PERFORMANCE TESTING; PLUTONIUM; RARE EARTHS; SCANNING ELECTRON MICROSCOPY; SPECTROSCOPY; SURFACE AREA; WASTE FORMS; WASTES; X-RAY DIFFRACTION; YUCCA MOUNTAIN

Citation Formats

Crawford, C, James Marra, J, and Ned Bibler, N. GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE GLASS FOR PLUTONIUM DISPOSITION. United States: N. p., 2007. Web. doi:10.1016/j.jallcom.2007.02.164.
Crawford, C, James Marra, J, & Ned Bibler, N. GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE GLASS FOR PLUTONIUM DISPOSITION. United States. doi:10.1016/j.jallcom.2007.02.164.
Crawford, C, James Marra, J, and Ned Bibler, N. Mon . "GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE GLASS FOR PLUTONIUM DISPOSITION". United States. doi:10.1016/j.jallcom.2007.02.164. https://www.osti.gov/servlets/purl/901093.
@article{osti_901093,
title = {GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE GLASS FOR PLUTONIUM DISPOSITION},
author = {Crawford, C and James Marra, J and Ned Bibler, N},
abstractNote = {The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) in Aiken, SC, 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. The objectives of this present task were to fabricate plutonium-loaded lanthanide borosilicate (LaBS) Frit B glass and perform testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the proposed Federal Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit B composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support glass durability testing via the ASTM Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was characterized with X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. This characterization revealed some crystalline PuO{sub 2} inclusions with disk-like morphology present in the as fabricated, quench-cooled glass. A series of PCTs was conducted at SRNL with varying exposed surface area and test durations. Filtered leachates from these tests were analyzed to determine the dissolved concentrations of key elements. The leachate solutions were also ultrafiltered to quantify colloid formation. Leached solids from select PCTs were examined in an attempt to evaluate the Pu and neutron absorber release behavior from the glass and to investigate formation of alteration phases on the glass surface. A series of PCTs was conducted at 90 C in ASTM Type 1 water to compare the Pu LaBS Frit B glass durability to current requirements for High Level Waste (HLW) glass in a geologic repository. The PCT (7-day static test with powdered glass) results on the Pu-containing LaBS Frit B glass at SA/V of {approx} 2000 m{sup -1} showed that the glass was very durable with an average normalized elemental release value for boron of 0.013 g/m{sup 2}. This boron release value is {approx} 640X lower than normalized boron release from current Environmental Assessment (EA) glass used for repository acceptance. The PCT-B (7, 14, 28 and 56-day, static test with powdered glass) normalized elemental releases were similar to the normalized elemental release values from PCT-A testing, indicating that the LaBS Frit B glass is very durable as measured by the PCT. Normalized plutonium releases were essentially the same within the analytical uncertainty of the ICP-MS methods used to quantify plutonium in the 0.45 {micro}m-filtered leachates and ultra-filtered leachates, indicating that colloidal plutonium species do not form under the PCT conditions used in this study.},
doi = {10.1016/j.jallcom.2007.02.164},
journal = {Journal of Alloys and Compounds},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2007},
month = {Mon Feb 12 00:00:00 EST 2007}
}
  • The 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 the preferred option for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium in the late 1990's. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Recent FY05 studiesmore » have further investigated the LaBS Frit B formulation as well as development of a newer LaBS formulation denoted as LaBS Frit X. The objectives of this present task were to fabricate plutonium loaded LaBS Frit X glass and perform corrosion testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit X composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was thoroughly characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL using quenched Pu Frit X glass with varying exposed surface areas. Effects of isothermal and can-in-canister heat treatments on the Pu Frit X glass were also investigated. Another series of PCTs were performed on these different heat-treated Pu Frit X glasses. Leachates from all these PCTs were analyzed to determine the dissolved concentrations of key elements. Acid stripping of leach vessels was performed to determine the concentration of the glass constituents that may have sorbed on the vessels during leach testing. Additionally, the leachate solutions were ultrafiltered to quantify colloid formation.« less
  • The 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 (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Therefore, the objectives of this present taskmore » were to fabricate plutonium loaded LaBS Frit B glass and perform additional testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit B composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL) and for additional performance testing at Argonne National Laboratory (ANL) and Pacific Northwest National Laboratory (PNNL). The glass was characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL with varying exposed surface area and test durations. The leachates from these tests were analyzed to determine the dissolved concentrations of key elements. Acid stripping of leach vessels was performed to determine the concentration of the glass constituents that may have sorbed on the vessels during leach testing. Additionally, the leachate solutions were ultrafiltered to quantify colloid formation. The leached solids from select PCTs were examined in an attempt to evaluate the Pu and neutron absorber release behavior from the glass and to identify the formation of alteration phases on the glass surface. Characterization of the glass prior to testing revealed that some undissolved plutonium oxide was present in the glass. The undissolved particles had a disk-like morphology and likely formed via coarsening of particles in areas compositionally enriched in plutonium. Similar disk-like PuO{sub 2} phases were observed in previous LaBS glass testing at PNNL. In that work, researchers concluded that plutonium formed with this morphology as a result of the leaching process. It was more likely that the presence of the plutonium oxide crystals in the PNNL testing was a result of glass fabrication. A series of PCTs were conducted at 90 C in ASTM Type 1 water. The PCT-Method A (PCT-A) was conducted to compare the Pu LaBS Frit B glass durability to current requirements for High Level Waste (HLW) glass in a geologic repository. The PCT-A test has a strict protocol and is designed to specifically be used to evaluate whether the chemical durability and elemental release characteristics of a nuclear waste glass have been consistently controlled during production and, thus, meet the repository acceptance requirements. The PCT-A results on the Pu containing LaBS Frit B glass showed that the glass was very durable with a normalized elemental release value for boron of approximately 0.02 g/L. This boron release value was better than two orders of magnitude better from a boron release standpoint than the current Environmental Assessment (EA) glass used for repository acceptance. The boron release value for EA glass is 16.7 g/L.« less
  • The 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 the preferred option for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium in the late 1990's. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Recent FY05 studiesmore » have further investigated the LaBS Frit B formulation as well as development of a newer LaBS formulation denoted as LaBS Frit X. The objectives of this present task were to fabricate plutonium loaded LaBS Frit X glass and perform corrosion testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit X composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was thoroughly characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL using quenched Pu Frit X glass with varying exposed surface areas. Effects of isothermal and can-in-canister heat treatments on the Pu Frit X glass were also investigated. Another series of PCTs were performed on these different heat-treated Pu Frit X glasses. Leachates from all these PCTs were analyzed to determine the dissolved concentrations of key elements. Acid stripping of leach vessels was performed to determine the concentration of the glass constituents that may have sorbed on the vessels during leach testing. Additionally, the leachate solutions were ultrafiltered to quantify colloid formation. Characterization of the quenched Pu Frit X glass prior to testing revealed that some crystalline plutonium oxide was present in the glass. The crystalline particles had a disklike morphology and likely formed via coarsening of particles in areas compositionally enriched in plutonium. Similar results had also been observed in previous Pu Frit B studies. Isothermal 1250 C heat-treated Pu Frit X glasses showed two different crystalline phases (PuO{sub 2} and Nd{sub 2}Hf{sub 2}O{sub 7}), as well as a peak shift in the XRD spectra that is likely due to a solid solution phase PuO{sub 2}-HfO{sub 2} formation. Micrographs of this glass showed a clustering of some of the crystalline phases. Pu Frit X glass subjected to the can-in-canister heating profile also displayed the two PuO{sub 2} and Nd{sub 2}Hf{sub 2}O{sub 7} phases from XRD analysis. Additional micrographs indicate crystalline phases in this glass were of varying forms (a spherical PuO{sub 2} phase that appeared to range in size from submicron to {approx}5 micron, a dendritic-type phase that was comprised of mixed lanthanides and plutonium, and a minor phase that contained Pu and Hf), and clustering of the phases was also observed.« less
  • A vitrification technology utilizing a lanthanide borosilicate (LaBS) glass is a viable option for dispositioning excess weapons-useable plutonium that is not suitable for processing into mixed oxide (MOX) fuel. A significant effort to develop a glass formulation and vitrification process to immobilize plutonium was completed in the mid-1990s. The LaBS glass formulation was found to be capable of immobilizing in excess of 10 wt % Pu and to be tolerant of a range of impurities. A more detailed study is now needed to quantify the ability of the glass to accommodate the anticipated impurities associated with the Pu feeds nowmore » slated for disposition. The database of Pu feeds was reviewed to identify impurity species and concentration ranges for these impurities. Based on this review, a statistically designed test matrix of glass compositions was developed to evaluate the ability of the LaBS glass to accommodate the impurities. Sixty surrogate LaBS glass compositions were prepared in accordance with the statistically designed test matrix. The heterogeneity (e.g. degree of crystallinity) and durability (as measured by the Product Consistency Test - Method A (PCT-A)) of the glasses were used to assess the effects of impurities on glass quality.« less
  • Laboratory tests were conducted with a lanthanide borosilicate (LaBS) glass made with Frit B and added PuO2 (the glass is referred to herein as Pu LaBS-B glass) to measure the dependence of the glass dissolution rate on pH and temperature. These results are compared with the dependencies used in the Defense HLW Glass Degradation Model that was developed to account for HLW glasses in total system performance assessment (TSPA) calculations for the Yucca Mountain repository to determine if that model can also be used to represent the release of radionuclides from disposed Pu LaBS glass by using either the samemore » parameter values that are used for HLW glasses or parameter values specific for Pu LaBS glass. Tests were conducted by immersing monolithic specimens of Pu LaBS-B glass in six solutions that imposed pH values between about pH 3.5 and pH 11, and then measuring the amounts of glass components released into solution. Tests were conducted at 40, 70, and 90 C for 1, 2, 3, 4, and 5 days at low glass-surface-area-to-solution volume ratios. As intended, these test conditions maintained sufficiently dilute solutions that the impacts of solution feedback effects on the dissolution rates were negligible in most tests. The glass dissolution rates were determined from the concentrations of Si and B measured in the test solutions. The dissolution rates determined from the releases of Si and B were consistent with the 'V' shaped pH dependence that is commonly seen for borosilicate glasses and is included in the Defense HLW Glass Degradation Model. The rate equation in that model (using the coefficients determined for HLW glasses) provides values that are higher than the Pu LaBS-B glass dissolution rates that were measured over the range of pH and temperature values that were studied (i.e., an upper bound). Separate coefficients for the rate expression in acidic and alkaline solutions were also determined from the test results to model Pu LaBS-B glass dissolution directly. The releases of Gd, Hf, and Pu from the glass were also measured. The release of Pu was significantly less than Si at all temperatures and pH values (on a normalized basis). More Gd than Pu or Hf was released from the glass in acidic solutions, but more Pu than Gd or Hf was released in alkaline solutions. Almost all of the released Gd remained in solution in tests conducted in Teflon vessels, whereas about half of the released Pu and Hf became fixed to the Teflon. In tests conducted in Type 304L stainless steel vessels, most of the released Gd, Hf, and Pu became fixed to the steel. The aqueous concentrations of Gd, Hf, and Pu decreased from about 2 x 10{sup -5}, 2 x 10{sup -8}, and 1 x 10{sup -7} M in tests solutions near pH 3.7 to about 1 x 10{sup -9}, 8 x 10{sup -10}, and 1 x 10{sup -8} M in test solutions near pH 10.8, respectively, in the 90 C tests in Teflon vessels (the solutions were not filtered prior to analysis). Vapor hydration tests (VHTs) were conducted at 120 and 200 C with Pu LaBS-B glass and SRL 418 glass, which was made to represent the HLW glass that will be used to macro-encapsulate LaBS glass within the waste form. Some VHTs were conducted with specimens of Pu LaBS-B and SRL 418 glasses that were in contact to study the effect of the solution generated as HLW glass dissolves on the corrosion behavior of Pu LaBS-B glass. Other VHTs were conducted in which the glasses were not in contact. The Pu LaBS-B glass is more durable than the HLW glass under these accelerating test conditions, even when the glasses are in contact. The presence of the SRL 418 glass did not promote the dissolution of the Pu LaBS-B glass significantly. However, Gd, Hf, and Pu were detected in alteration phases formed on the Pu LaBS-B glass surface and in (or on) phases formed by SRL 418 glass degradation, such as analcime. This indicates that Gd, Hf, and Pu were transported from the LaBS glass, through the water film formed on the specimens, and to the SRL 418 glass during the test. The disposition of the PuO{sub 2} inclusion phases as the Pu LaBS-B glass dissolved was not determined. They were observed in the glass underlying the alteration layers, but were not detected among the alteration phases.« less