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The U.S. Department of Energy Hanford Site in Washington State is in the process of commissioning the Waste Treatment and Immobilization Plant to process a portion of the 54 million gallons of radioactive and chemical waste from cold war weapon production. Technologies for the capture of volatile species of concern are still being assessed, and new methods and materials are developed as operational and flowsheet mission risks are identified. One such area still being assessed is the abatement efficacy of the Carbon Adsorber units to retain gaseous mercury and ¹²⁹I released during processing. It is challenging to predict the mercurymore » chemistry due to the variability of the feed, and different methods/materials are required for the capture of gaseous Hg⁰ and Hg^II compounds. In this study, the feasibility of using developmental carbon foam (CF) sorbents for the capture of iodine and mercury was assessed using static and dynamic flow testing and compared against a commercially available sorbent, BATII-37. Both CF and CF functionalized with bismuth particles (CF-Bi) chemisorbed iodine, and CF-Bi had similar mercury capture performance to BATII-37 in dynamic flow tests. While species loading concentrations were measurable, limitations in achieving a mass balance prevented a full evaluation of capture efficacy. Nonetheless, the results serve as an important first step in demonstrating the potential for simultaneous iodine and mercury capture.« less

Here, this paper reports the hygroscopic properties of eutectic LiCl-KCl after absorption into zeolite-4A, up to salt loadings of 75 wt%. Samples of the salt occluded zeolite were hydrated in a humidity chamber at constant temperature and relative humidity for up to 100 h. At up to 45 wt% salt loading, the un-occluded phase of salt consisted primarily of NaCl, which forms when the Na⁺ ions present in the zeolite framework exchange with Li⁺ and K⁺ ions from the eutectic LiCl-KCl. This results in minimal water absorption and corrosion of contacted stainless steel. At greater than 45 wt% salt loading,more » water absorption and corrosion progressively worsened. The mixture has a significant amount of excess LiCl-KCl, making it highly hygroscopic. This study reveals an option for the intermediate treatment of waste salt from spent nuclear fuel electrorefiners that could facilitate it to be stored in a non-inert atmosphere for extended periods of time before final conversion into a permanent waste form.« less

Abstract Bismuth aluminoborosilicate glasses were prepared using a standard melt‐quench technique, and the viscosity and thermal properties were measured and analyzed. Electron microprobe analysis was used to examine glass homogeneity. Fragility was calculated based on Mauro–Yue–Ellison–Gupta–Allan model fits to the viscosity curves. The system is characterized by an open structure with high fragility (44‐59). Based on microanalysis and differential scanning calorimetry results, the addition of network intermediate Al ₂ O ₃ appears to mitigate both phase separation and crystallization. From thermal property data, mixture models were created to predict the glass transition temperatures and softening temperatures as functions of composition.more » Based on K‐fold validation findings, the first‐order mixture model predictions of glass transition and softening appear to approximate actual values better than models with any additional second‐order terms.« less