Salt-Zeolite Ion-Exchange Equilibrium Studies for a Complete Set of Fission Products in Molten LiCl-KCl

This paper presents results of experiments and modeling for ion exchange of LiCl-KCl-based molten salts with zeolite-A. The experiments examined the equilibrium distributions of various nuclear fuel fission products between the molten salt and zeolite phases. In addition to data that were collected in previous studies, new experiments were run using ternary salts (LiCl-KCl-YCl 3 , LiCl-KCl-LaCl 3 , and LiCl-KCl-PrCl 3 ) and quaternary salts (LiCl-KCl-CsCl-NdCl 3 and LiCl-KCl-CsCl-SrCl 2 ). All contacting experiments were conducted at 500°C with a salt-zeolite contacting period of 24 h to allow for equilibrium to be reached. The developed equilibrium model assumes that there are ion-exchange and occlusion sites, both of which are in equilibrium with the molten salt phase. A systematic approach in estimating the total occlusion capacity of the zeolite-A was developed. The parameters of the model, including the total occlusion capacity of the zeolite-A, were determined from fitting the entire set of experimental data available between previous studies and the current one. Experiments involving ternary salts were used to estimate the parameters of the model, while those involving quaternary salts were used to validate the model.