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Title: The Behavior of Iodine in Stabilized Granular Activated Carbon and Silver Mordenite in Cementitious Waste Forms

Journal Article · · Journal of Environmental Radioactivity

Both granular activated carbon (GAC) and silver mordenite (AgM) are utilized for the removal of contaminants and radionuclides (e.g., radioiodine) from the off-gas streams in nuclear fuel reprocessing and high temperature immobilization of nuclear waste. Following their service lifetimes, the GAC and AgM contain an inventory of contaminants and/or radionuclides and require stabilization in a matrix for disposal. Cementitious waste forms can be used as the stabilization matrix for GAC and AgM, however, for successfully stabilization, the inclusion of GAC and AgM should not negatively impact the physical behavior of the cementitious waste form or the increase the release of the contaminants/radionuclides compared to the baseline case without stabilization. The present work focuses on evaluation of cement formulations, with and without slag, for the stabilization of iodine-loaded GAC or AgM. The results showed that both a slag-containing and slag-free formulation were able to stabilize GAC and AgM, up to 30 vol%, without deleterious impacts on the bulk physical properties of the resulting waste form. When monolithic samples of the GAC or AgM containing cement formulations were subjected to leach tests, it was observed that iodide leached from the SSW had limited sorption to either of the cement matrices but the iodine can interact with the SSW materials themselves. Specifically, iodine retention within monolithic samples containing the iodine-loaded GAC or AgM was improved for AgM containing waste forms while no improvement was observed for the GAC containing waste forms. The improvement for the AgM containing waste forms was likely due to an enrichment of Ag at the interface between the AgM particles and the cement matrix that can impede iodine migration out from the waste form. The results are significant in highlighting the potential for long-term retention of iodine in cementitious waste forms.

Research Organization:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1846380
Report Number(s):
PNNL-SA-165944
Journal Information:
Journal of Environmental Radioactivity, Vol. 244-245
Country of Publication:
United States
Language:
English

References (26)

Structural Insight into Iodide Uptake by AFm Phases journal March 2012
Silver-functionalized silica aerogels and their application in the removal of iodine from aqueous environments journal November 2019
Silver-based getters for 129I removal from low-activity waste journal January 2016
The use of silver as a selective precipitant for 129I in radioactive waste management journal January 1990
Behavior of iodate substituted ettringite during aqueous leaching journal February 2021
Do nuclear and renewable energy improve the environment? Empirical evidence from the United States journal July 2016
Development of a Geochemical Speciation Model for Use in Evaluating Leaching from a Cementitious Radioactive Waste Form journal June 2021
Evaluation of ettringite and hydrocalumite formation for heavy metal immobilization: Literature review and experimental study journal August 2006
Spectroscopic and first-principles investigations of iodine species incorporation into ettringite: Implications for iodine migration in cement waste forms journal May 2020
Radioiodine Biogeochemistry and Prevalence in Groundwater journal August 2014
Iodine speciation in a silver-amended cementitious system journal May 2019
Incorporation Modes of Iodate in Calcite journal April 2018
Light at the End of the Radwaste Disposal Tunnel Could Be Real journal July 2011
Iodine immobilization by silver-impregnated granular activated carbon in cementitious systems journal November 2019
Iodine immobilization by materials through sorption and redox-driven processes: A literature review journal May 2020
A review of the behavior of radioiodine in the subsurface at two DOE sites journal November 2019
Evolution of ettringite in presence of carbonate, and silicate ions journal December 2003
Characterizing Technetium in Subsurface Sediments for Contaminant Remediation journal September 2018
Chalcogen-Based Aerogels As Sorbents for Radionuclide Remediation journal June 2013
Chromate Effect on Iodate Incorporation into Calcite journal May 2019
Reducing future CO2 emissions — The role of nuclear energy journal January 1998
Solidification and stabilization of silver mordenite used to control radioiodine emissions from Hanford’s Waste Treatment Plant journal April 2015
Iodine and microbial interactions in an organic soil journal January 1995
A Closed-form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils1 journal January 1980
Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site journal January 2015
Iodine-129 and Iodine-127 Speciation in Groundwater at the Hanford Site, U.S.: Iodate Incorporation into Calcite journal August 2013