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

Journal Article · Mon Dec 01 00:00:00 EST 2014 · Journal of Non-Crystalline Solids

DOI:https://doi.org/10.1016/j.jnoncrysol.2014.08.053· OSTI ID:1170086

Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane; Wang, Zhaoying; Zhu, Zihua; Ryan, Joseph V.

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, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally 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 glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, with a non-aqueous solution of ⁶LiCl 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-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, D_Li, were then calculated based on the measured depth profiles. The results indicate that the penetration of ⁶Li is rapid in both glasses with the simplified CJ-6 glass (D_6Li ≈ 4.0-8.0 × 10^-21 m²/s) exhibiting faster exchange than the more complex SON68 glass (D_Li ≈ 2.0-4.0 × 10^-21 m²/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1170086
• Report Number(s): PNNL-SA-104115; 47580; AF5805010; TRN: US1500012
• Journal Information: Journal of Non-Crystalline Solids, Vol. 405; ISSN 0022-3093
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
LITHIUM
LITHIUM IONS
INDIUM IONS
SODIUM IONS
AQUEOUS SOLUTIONS
HIGH-LEVEL RADIOACTIVE WASTES
RADIOACTIVE WASTE DISPOSAL
MASS SPECTROSCOPY
ION MICROPROBE ANALYSIS
BOROSILICATE GLASS
BORON SILICATES
ALUMINIUM SILICATES
TEMPERATURE RANGE 0065-0273 K
DIFFUSION
DMSO
CORROSION
DEPTH
LAYERS
SIMULATION
WATER
ION EXCHANGE
TIME-OF-FLIGHT METHOD
ABUNDANCE
COMPLEXES
INTEGRALS
PERFORMANCE
SOLIDS
RADIOACTIVE WASTE FACILITIES
lithium diffusion
nuclear waste glass
long-term corrosion
isotope tracking
Environmental Molecular Sciences Laboratory