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Optimization of sintered AgI-Mordenite composites for {sup 129}I storage

Conference ·
OSTI ID:22264227
; ; ; ;  [1]
  1. Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185-1411 (United States)

The thermal processing of a proposed durable waste form for {sup 129}I was investigated. The waste form is a composite with a matrix of low-temperature sintering glass that encapsulates particles of AgI-mordenite. Ag-mordenite, an ion-exchanged zeolite, is being considered as a capture medium for gaseous {sup 129}I{sub 2} as part of a spent nuclear fuel reprocessing scheme under development by the US Department of Energy/Nuclear Energy (NE). The thermal processing of the waste form is necessary to increase the density of the glass matrix by viscous sintering so that the final waste form does not have any open porosity. Other processes that can also occur during the thermal treatment include desorption of chemisorbed I{sub 2}, volatilization of AgI and crystallization of the glass matrix. We have optimized the thermal processing to achieve the desired high density with higher AgI-mordenite loading levels and with minimal loss of iodine. Using these conditions, 625 C. degrees for 20 minutes, the matrix crystallizes to form a eulytite phase. Results of durability tests indicate that the matrix crystallization does not significantly decrease the durability in aqueous environments. (authors)

Research Organization:
American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
OSTI ID:
22264227
Country of Publication:
United States
Language:
English