Rhenium Solubility in Borosilicate Nuclear Waste Glass: Implications for the Processing and Immobilization of Technetium-99

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• 作者：John S. McCloy ; Brian J. Riley ; Ashutosh Goel ; Martin Liezers ; Michael J. Schweiger ; Carmen P. Rodriguez ; Pavel Hrma ; Dong-Sang Kim ; Wayne W. Lukens ; Albert A. Kruger
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：November 20, 2012
• 年：2012
• 卷：46
• 期：22
• 页码：12616-12622
• 全文大小：297K
• 年卷期：v.46,no.22(November 20, 2012)
• ISSN：1520-5851

文摘

The immobilization of technetium-99 (⁹⁹Tc) in a suitable host matrix has proven to be a challenging task for researchers in the nuclear waste community around the world. In this context, the present work reports on the solubility and retention of rhenium, a nonradioactive surrogate for ⁹⁹Tc, in a sodium borosilicate glass. Glasses containing target Re concentrations from 0 to 10鈥?00 ppm [by mass, added as KReO₄ (Re⁷⁺)] were synthesized in vacuum-sealed quartz ampules to minimize the loss of Re from volatilization during melting at 1000 掳C. The rhenium was found as Re⁷⁺ in all of the glasses as observed by X-ray absorption near-edge structure. The solubility of Re in borosilicate glasses was determined to be 3000 ppm (by mass) using inductively coupled plasma optical emission spectroscopy. At higher rhenium concentrations, additional rhenium was retained in the glasses as crystalline inclusions of alkali perrhenates detected with X-ray diffraction. Since ⁹⁹Tc concentrations in a glass waste form are predicted to be <10 ppm (by mass), these Re results implied that the solubility should not be a limiting factor in processing radioactive wastes, assuming Tc as Tc⁷⁺ and similarities between Re⁷⁺ and Tc⁷⁺ behavior in this glass system.