A Simple Model Predicting Iodine Profile in a Packed Bed of Silica-Gel Impregnated with Silver Nitrate

Abstract

Based on a simple adsorption theory, a mathematical model was proposed to predict axial iodine profiles of the column of silica gel impregnated with silver nitrate (hereinafter referred to as Ag-S) in an off-gas treatment system for spent fuel dissolution. The unknown parameters of the model: the effective diffusion coefficient D_ea and the Langmuir coefficient K were determined by curve fitting of iodine profile experimentally obtained. At 423 K, D_ea and K were found to be 5.60×10^-7 m².s^-1 and 1.0×10⁵ m³.kg^-1, respectively. Using the parameter values, the model could well predict the iodine profiles obtained at 423 K in the previous works under different experimental conditions. Furthermore, the effect of silver contents on the iodine profiles was reasonably predicted. It was suggested that the proposed model is simple and would be useful to predict the iodine profiles in Ag-S adsorbent columns.

KEYWORDS:

• adsorption
• head-end process
• iodine 129
• mathematical model
• reprocessing
• silica gel
• silver iodates
• silver iodides
• silver nitrates
• diffusion coefficient
• Langmuir coefficient