Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

Pierce, Eric M.; McGrail, B. Peter; Bagaasen, Larry M.; Rodriguez, Elsa A.; Wellman, Dawn M.; Geiszler, Keith N.; Baum, Steven R.; Reed, Lunde R.; Crum, Jarrod V.; Schaef, Herbert T.

doi:10.2172/908206

Cited by 8 publications

(3 citation statements)

References 31 publications

(13 reference statements)

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“…Na ion-exchange rate, mol m -2 s -1 1.5110 -8 Secondary phases are solids that precipitate from a supersaturated aqueous solution. Potential secondary phases and their equilibrium constant values were determined using long-term weathering experiments with the various waste glass formulations and by modeling the analyzed solutions with the EQ3/6 code (Pierce et al 2004b). The secondary phase and corresponding log K at 99ºC added to the geochemical database for the simulations are provided in Table 7.4 and were identified by simulating the dissolution of waste glass in DIW at 99C with the EQ3/6 code package (Wolery and Jarek 2003).…”

Section: Puf Test Simulation Descriptionmentioning

confidence: 99%

“…-5.4 Baddeleyite + 2H 2 O = Zr(OH) 4 (aq) -5.2 Clinochlore-14Å = 3SiO 2 (aq) +5Mg 2+ + 8OH -+ 2AlO 2 --79.0 Diaspore = AlO 2 -+ OH --4.7 Zn(OH) 2 (gamma) = 2OH -+ Zn 2+ -15.0 (a) All data were fit to SPFT data for LAWA44 glass (Pierce et al 2004b) -5.26 ZnPO 4 -= OH -+ HPO 4 2-+ Zn 2+ -7.97 (a) All data were obtained from the EQ3/6 data0.com.R8 database (Daveler and Wolery 1992).…”

Section: Puf Test Simulation Descriptionmentioning

confidence: 99%

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Integrated Disposal Facility FY2010 Glass Testing Summary Report

Pierce¹,

Bacon²,

Kerisit³

et al. 2010

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Pacific Northwest National Laboratory was contracted by Washington River Protection Solutions, LLC to provide the technical basis for estimating radionuclide release from the engineered portion of the disposal facility (e.g., source term). Vitrifying the low-activity waste at Hanford is expected to generate over 1.6 × 10 5 m 3 of glass (Puigh 1999). The volume of immobilized low-activity waste (ILAW) at Hanford is the largest in the DOE complex and is one of the largest inventories (approximately 0.89 × 10 18 Bq total activity) of long-lived radionuclides, principally 99 Tc (t 1/2 = 2.1 × 10 5), planned for disposal in a low-level waste (LLW) facility. Before the ILAW can be disposed, DOE must conduct a performance assessement (PA) for the Integrated Disposal Facility (IDF) that describes the long-term impacts of the disposal facility on public health and environmental resources. As part of the ILAW glass testing program PNNL is implementing a strategy, consisting of experimentation and modeling, in order to provide the technical basis for estimating radionuclide release from the glass waste form in support of future IDF PAs. The purpose of this report is to summarize the progress made in fiscal year (FY) 2010 toward implementing the strategy with the goal of developing an understanding of the long-term corrosion behavior of low-activity waste glasses. The emphasis in FY2010 was the completing an evaluation of the most sensitive kinetic rate law parameters used to predict glass weathering, documented in Bacon and Pierce (2010), and transitioning from the use of the Subsurface Transport Over Reactive Multi-phases to Subsurface Transport Over Multiple Phases computer code for near-field calculations. The FY2010 activities also consisted of developing a Monte Carlo and Geochemical Modeling framework that links glass composition to alteration phase formation by 1) determining the structure of unreacted and reacted glasses for use as input information into Monte Carlo calculations, 2) compiling the solution data and alteration phases identified from accelerated weathering tests conducted with ILAW glass by PNNL and Viteous State Laboratory/Catholic University of America as well as other literature sources for use in geochemical modeling calculations, and 3) conducting several initial calculations on glasses that contain the four major components of ILAW

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Section: Puf Test Simulation Descriptionmentioning

confidence: 99%

Section: Puf Test Simulation Descriptionmentioning

confidence: 99%

Integrated Disposal Facility FY2010 Glass Testing Summary Report

Pierce¹,

Bacon²,

Kerisit³

et al. 2010

Self Cite

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show abstract

“…Although ion exchange has not received the level of attention that network hydrolysis and matrix dissolution have, it has been the focus of some studies in nuclear waste glasses (Icenhower et al, 2002;McGrail et al, 2003;McGrail et al, 2001;Ojovan et al, 2006;Pierce et al, 2005). With the exception of Ojovan et al (2006), who modelled release rates of radionuclides using diffusion controlled ion exchange (i.e.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

Neeway

Kerisit

Gin

et al. 2014

Journal of Non-Crystalline Solids

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Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water during the corrosion process, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other simultaneously occurring processes. In this work, an inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting simulated nuclear waste glass coupons, the 6-oxide CJ-6 and the 26oxide SON68, with a non-aqueous solution of 6 LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-offlight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6 Li is faster in the simplified CJ-6 (D6Li ≈ 4.0-8.0 × 10-21 m 2 /s) compared to the more complex SON68 (D6Li ≈ 2.0

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Current Understanding and Remaining Challenges in Modeling Long‐Term Degradation of Borosilicate Nuclear Waste Glasses

Vienna

Ryan

Gin

et al. 2013

Int J of Appl Glass Sci

218

195

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Chemical durability is not a single material property that can be uniquely measured. Instead, it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment and modeling. High‐level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long‐term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near‐field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time scales. This article summarizes the current state of understanding of surface reactions, transport properties and ion exchange along with the near‐field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps.

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Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

Cited by 8 publications

References 31 publications

Integrated Disposal Facility FY2010 Glass Testing Summary Report

Integrated Disposal Facility FY2010 Glass Testing Summary Report

Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

Current Understanding and Remaining Challenges in Modeling Long‐Term Degradation of Borosilicate Nuclear Waste Glasses

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