<sup>129</sup>Iodine is a volatile fission product generated during nuclear power production and released during reprocessing of spent nuclear fuel.  With increasing attention focused on liquid-fueled reactors, such as the molten salt reactor, and an increasingly urgent need for reducing the volume of spent nuclear fuel requiring long-term disposal, development of materials capable of selectively binding gaseous iodine are a critical need for nuclear power production. Silver-exchanged mordenite remains the baseline material investigated for iodine capture, having been investigated for neary five decades.  However, the majority of such studies have focused on the macroscopic properties of the material, rather than the underlying molecular interactions which govern the observed performance.<br/>This talk will cover our application of x-ray absorption fine structure (XAFS)spectroscopy to investigate the activation, iodine capture, regeneration, and recycle of silver exchanged mordenite -- the first instance XAFS was used to investigate this process.  Our more recent work will also be surveyed, where XAFS and pair distribution function profiles from high energy x-ray scattering were applied to determine the deactivation pathways impeding iodine uptake.  Finally, time permitting, ongoing efforts regarding the application of RMC Profile will be discussed.  RMC Profile applies reverse Monte Carlo techniques to self-consistently refine multiple data sets from various techniques to determine a structure model that is consistent across multiple spatial regimes.  In our case, high-energy powder diffraction, pair distribution function data, and XAFS at Ag and I K-edges will be analyzed to afford the best comprehensive structural assessment of silver-exchanged mordenites to date.

X-ray absorption spectroscopy and pair distribution function investigations of iodine-capture and deactivation of silver-exchanged mordenite for application in nuclear fuel reprocessing and advanced nuclear reactors

255th National Meeting (2018)

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