Methyl Iodide Adsorption Test Results
Of the four volatile radionuclides that may require removal from the off-gas streams of a US-sited used nuclear fuel reprocessing plant (3H, 14C, 85Kr, and 129I), 129I is expected to require the greatest efficiency of removal. Historically, the removal of organic iodine species has been considered more difficult than the removal of elemental iodine (I2). In 2012, Oak Ridge National Laboratory (ORNL), Idaho National Laboratory (INL), Pacific Northwest National Laboratory (PNNL), and Sandia National Laboratory (SNL) released a joint test plan designed to better understand the adsorption of organic iodine, specifically methyl iodide (CH3I) by silver mordenite (AgZ). Repeated observations by INL have confirmed the presence of elemental iodine (I2) in the effluent of AgZ deep beds, even though methyl iodide (CH3I) is the sole iodine species in the feed gas. The intent of the joint test plan was to identify key questions about the behavior of CH3I when adsorbed by AgZ and to ensure that previously observed INL data were validated by duplicate testing. The test plan was expected to proceed through multiple stages, and the purpose of this report is to document the results of Phase 1 testing prescribed by the joint test plan, which was conducted at ORNL. INL has reported its corresponding test results, and synthesis of ORNL and INL results is expected to be completed in the near future. The forthcoming report will answer some of the questions identified by the joint test plan. Seven thin bed tests characterizing the adsorption of CH3I and I2 by AgZ and NaZ were performed. The first three tests examined the effects of NOX and H2O on CH3I adsorption by AgZ and found that a 43% reduction in iodine capacity occurred when NOX was present in the feed stream (as compared to CH3I adsorption from a dry air stream) and that a 23% reduction in iodine capacity occurred when both NOX and H2O were present in the feed stream.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1606724
- Report Number(s):
- ORNL/SPR-2019/1433; TRN: US2103939
- Country of Publication:
- United States
- Language:
- English
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