Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jan 11:10:1078668.
doi: 10.3389/fchem.2022.1078668. eCollection 2022.

Abatement of radioiodine in aqueous reprocessing off-gas

Allison T Greaney  1 , Randy O Ngelale  1 , Stephanie H Bruffey  2 , Leigh R Martin  1
Affiliations

Abatement of radioiodine in aqueous reprocessing off-gas

Allison T Greaney et al. Front Chem. .

Abstract

The reprocessing used nuclear fuel (UNF) releases volatile fission and activation products, including 129I, into the off-gas of a processing plant. Mitigation of the release of vapor phase radionuclides is necessary for meeting regulatory requirements in the United States and other countries. In an aqueous reprocessing plant, volatile radioiodine could be present in several forms, depending on the chemistry of the process used. Inorganic iodine will be the predominate species in any shearing or voloxidation pretreatment off-gas and dissolver off-gas (DOG). Organic iodides such as CH3I, C4H9I, and C12H25I have been proposed to be generated during solvent extraction; thus, these species must be captured from the vessel off-gas (VOG). The abatement of inorganic and organic iodide species to meet United States regulatory requirements has been demonstrated in laboratory experiments using Ag-based solid sorbents. The data presented in this paper includes the effect of gas composition (e.g., the presence of water vapor and NO x ), iodine speciation (I2, CH3I, C4H9I, C12H25I), and sorbent bed parameters (e.g., temperature, sorbent age) on complete iodine capture on Ag-mordenite in an aqueous reprocessing plant.

Keywords: aqueous reprocessing; off-gas; organic iodide; radioiodine; silver mordenite.

PubMed Disclaimer

Conflict of interest statement

SB is employed by Ultra Safe Nuclear Corporation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Diagram of an aqueous reprocessing facility with estimated iodine partitioning through the plant expressed as a percentage of the total initial used nuclear fuel (UNF) iodine inventory.
FIGURE 2
FIGURE 2
Photograph of the TGA thin bed that contains AgZ pellets that reacted with iodine to form AgI or AgIO3 (green pellets at end of arrow) (left); schematic of the manifold used for TGA testing at ORNL (right). OI (right figure) represents organic iodide spargers.
FIGURE 3
FIGURE 3
Effects of each temperature, dew point, NO2 vol%, and NO vol% on I2 and CH3I sorption (mg I/g sorbent) on AgZ. Each box and whisker plot represents iodine loading results of four tests. Iodine data are in blue (left-hand boxes), and CH3I data are in orange (right-hand boxes).
FIGURE 4
FIGURE 4
Summary of organic iodide experimental results. (Top) Effects of organic iodide chain length and concentration on total loading rate. (Bottom) Effects of sorbent aging on total sorbent capacity for organic iodide adsorption.
See this image and copyright information in PMC

References

    1. Birdwell J. F. (1990). “Iodine and NOx behavior in the dissolver off-gas and IODOX systems in the Oak Ridge National laboratory integrated equipment test facility,” in Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference, San Diego, California, 13-16 August 1990 (Oak Ridge National Laboratory; ).
    1. Bruffey S. H., Greaney A. T., Jubin R. T., Soelberg N. R., Welty A. (2019). Kinetics of aging process on reduced Ag exchanged mordenite in dry air and humid air. AIChE J. 67, e17182. 10.1002/aic.17182 - DOI
    1. Bruffey S., Spencer B. B., Strachan D. M., Jubin R. T., Soelberg N. R., Riley B. J. (2015). “A literature survey to identify potentially problematic volatile iodine-bearing species present in off-gas streams,”. ORNL-SPR-2015/290.
    1. J. A Dean, (Editor) (1999). Lange’s handbook of chemistry. 15th edition (New York, United States: McGraw-Hill; ).
    1. EPA-1 (1977). Protection of environment: Chapter I–environmental protection agency (continued), environmental radiation protection standards for nuclear power Operations 40CFR190.10. Washington, DC: US Environmental Protection Agency.

LinkOut - more resources