Ion Exchange Processes and Mechanisms in Glasses

McGrail, B. Peter ; Baer, D. R. ; Darab, J. G. ; Icenhower, J. P. ; Shuh, D. K.

Lawrence Berkeley National Laboratory

关键词: Corrosion;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Hydroxides;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Kinetics;   

DOI  :  10.2172/829972
RP-ID  :  EMSP-60362--2000
RP-ID  :  829972

美国|英语

来源: UNT Digital Library

【 摘 要 】

Plans for immobilizing low-activity radioactive tank wastes at the Hanford Site call for vitrification followed by shallow subsurface disposal. Water percolating through the disposal system will eventually react with the vitrified waste, releasing the encapsulated radionuclides. Consequently, it is important to understand the glass corrosion mechanisms that ultimately control the radionuclide release rate. One important reaction involves the exchange of alkali ions in the glass with H+ or H3O+ ions in water, which raises the pH in the disposal system and can enhance 99Tc release rates by 100X or more. The objective of this work is to develop an understanding of the processes and mechanisms controlling alkali ion exchange and to correlate the kinetics of the ion-exchange reaction with glass structural properties. The fundamental understanding of the ion-exchange process developed under this study is targeted at developing lower ion-exchange rate glasses that would remain durable at higher alkali waste loading.