Masters Theses

Orcid ID

Date of Award


Degree Type


Degree Name

Master of Science


Nuclear Engineering

Major Professor

Howard Hall

Committee Members

John D. Auxier II, Steven Skutnik


United States regulations on nuclear reprocessing would limit the release of certain radioactive volatile species, including 3H, 14C, 85Kr, and 129I. Conservative analyses indicate that >99.9% of the iodine contained in used nuclear fuel could require capture. Solid sorbents for this application include silver mordenite (AgZ) and silver nitrate–impregnated alumina (AgA). AgA has been studied previously under simulated possible reprocessing conditions to assess its effectiveness as an iodine sorbent, and those results have been compared with well-characterized AgZ.To date, AgZ and AgA have been investigated for use in iodine capture from off-gas generated by aqueous fuel reprocessing. However, modifications to traditional reprocessing have been considered, including upfront tritium pretreatment using NO2 as the oxidant. This introduces large amounts of NO2 to the off-gas, which has been shown to severely degrade the iodine capture performance of AgZ. Literature regarding the behavior of AgA in NO2-bearing gas streams suggested that AgA could be better able to retain its iodine-capture capabilities under these high-NO2 conditions. This hypothesis was tested by exposing AgA to a high-NO2 environment for varying periods of time and then measuring the iodine capacity of the sorbent. AgA retained 85%, 65%, and 25% of its capture capacity when exposed to NO2 for 1 week, 2 weeks, and 4 weeks prior to testing, respectively. When aged for 1 week and 4 weeks, AgZ only retained 3% and 8% of its capture capacity. In non-oxidizing conditions, the capture performance of the sorbents is similar. Thus, this thesis supports the theory that AgA is more robust to the presence of NO2 than AgZ and merits further consideration if advanced tritium pretreatment is to be performed during fuel reprocessing.

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