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Helium Solubility in SON68 Nuclear Waste Glass
Author(s) -
Fares Toby,
Peuget Sylvain,
Chamssedine Fadel,
Sauvage Thierry,
Bouty Olivier,
Broudic Véronique,
Deschanels Xavier,
Maugeri Emilio,
Bes René,
Jégou Christophe
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12048
Subject(s) - helium , borosilicate glass , solubility , materials science , microstructure , analytical chemistry (journal) , diffusion , composite material , thermodynamics , chemistry , organic chemistry , physics
Helium behavior in a sodium borosilicate glass (SON68) dedicated to the immobilization of high‐level nuclear waste is examined. Two experimental approaches on nonradioactive glass specimens are implemented: pressurized helium infusion experiments and 3 He ion implantation experiments. The temperature variation of helium solubility in SON68 glass was determined and analyzed with the harmonic oscillator model to determine values of the energy of interaction E (0) at the host sites (about −4000 J/mol), the vibration frequency (about 1.7 × 10 11 s −1 ), and the density of solubility sites (2.2 × 10 21 sites cm −3 ). The implantation experiments show that a nondiffusive transport phenomenon (i.e., athermal diffusion) is involved in the material when the helium concentration exceeds 2.3 × 10 21 He cm −3 , and thus probably as soon as it exceeds the density of solubility sites accessible to helium in the glass. We propose that this transport mechanism could be associated with the relaxation of the stress gradient induced by the implanted helium profile, which is favored by the glass damage. Microstructural characterization by TEM and ESEM of glass specimens implanted with high helium concentrations showed a homogeneous microstructure free of bubbles, pores, or cracking at a scale of 10 nm.