Silver as a capturing material for iodine released from lead–bismuth eutectic in various conditions

Abstract

The usage of silver as a filtering material for removal of iodine from the gas phase of a lead–bismuth eutectic based nuclear reactor was investigated in various atmospheres representing normal operation as well as accident conditions. Thermochromatography experiments were performed to quantify the retention experienced on a silver surface by iodine species evaporated from a lead–bismuth eutectic sample. Measured adsorption enthalpies ranged from −171 to − 208 kJ mol−1 with observed differences attributed to various surface effects rather than a change in iodine speciation. The postulated adsorption mechanism is chemisorption of iodine atoms on the silver surface. Metallic silver fulfills the desired criteria for a capturing material in water-free filtering systems to be used as an alternative to traditional alkaline scrubbers commonly used in LWR systems.

Recent Advances in the Removal of Radioactive Iodine and Iodide from the Environment

“…A column covered with silver foil (Goodfellow, 0.020 ± 0.003 mm, purity = 99.9%) on the inner surface was used to adsorb radioactive I 2 that was produced by a MYRRHA reactor, a lead–bismuth eutectic cooled proton accelerator driven system. The silver material effectively adsorbed I 2 evaporated from the eutectic mixture at all tested conditions . A silver-functionalized silica aerogel (AgAero) was tested for the safe sequestration of radioactive iodine from nuclear waste streams and subsurface environments.…”

“…The silver material effectively adsorbed I 2 evaporated from the eutectic mixture at all tested conditions. 64 A silver-functionalized silica aerogel (AgAero) was tested for the safe sequestration of radioactive iodine from nuclear waste streams and subsurface environments. The AgAero exhibited selective, rapid, and complete removal of I 2 from deionized water, which was better than Hanford Site Waste Treatment Plant samples containing 5 to 10 ppm of I 2 .…”