Thesis
Aqueous synthesis of iodide sodalite for the immobilization of I-129
Washington State University
Master of Science (MS), Washington State University
2016
Handle:
https://hdl.handle.net/2376/100859
Abstract
129I is a nuclear fission product that is a highly volatile radionuclide and is difficult to immobilize in a waste form using conventional vitrification processes. It has a very long half-life of about 16 million years and is also highly water soluble, which poses a serious concern for storage in geological respositories. Attempts have been made using vitrification processes and in cements, but iodine typically has low solubility in some glass chemistries and it is highly volatile at typical glass processing temperatures between 1000-1100°C. Cement forms have also been attempted in the past, but iodine is highly soluble in cement pores which causes them to leach. Iodide sodalite has been shown to be synthesized at low temperatures below 200°C, and is thus the focus of this study. The main objective of this thesis was to investigate an innovative aqueous synthesis procedure for iodide sodalite. Synthesis conditions were varied such as precursor routes, drying temperatures, pH and precursor concentrations to maximize the yield of crystalline iodide sodalite. A synthesis procedure was established with a maximum iodide sodalite phase purity of 95% using a kaolinite-based precursor route by drying at 100°C with 15 mL of deionized water, while its measured density was 99.4% of the theoretical value. A sample with this high phase purity and density before sintering has never been reported before by aqueous or hydrothermal synthesis of iodide sodalite.
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Details
- Title
- Aqueous synthesis of iodide sodalite for the immobilization of I-129
- Creators
- Junghune Nam
- Contributors
- John McCloy (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525072201842
- Language
- English
- Resource Type
- Thesis