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

作者：McCloy John S^*; Riley Brian J; Goel Ashutosh; Liezers Martin; Schweiger Michael J; Rodriguez Carmen P; Hrma Pavel; Kim Dong Sang

来源：Environmental Science & Technology, 2012, 46(22): 12616-12622.

DOI：10.1021/es302734y

The immobilization of technetium-99 (Tc-99) 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 Tc-99, in a sodium borosilicate glass. Glasses containing target Re concentrations from 0 to 10 000 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 degrees 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 similar to 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 Tc-99 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.

• 出版日期2012-11-20