The feasibility study on development of porous ceramic composites for ion-exchanger

Abstract

During normal operation of the nuclear reactor, several corrosion elements (CRUD) can be produced due to the degradation of the reactor structural materials. These impurities must be removed from the reactor coolant system to preserve the performance of the reactor coolant. We are developing a new porous ceramic adsorption material to replace current bead-type polystyrene resins at the ion exchanger. We performed experimental and numerical studies to investigate the feasibility of using Zeolite as a ceramic ion-exchange composite, which is stable at high temperatures and has high adsorption capacity for the constituent elements of CRUD. We are also proposing a new configuration of the ceramic composite, which is a Twisted Honeycomb shape printed by a 3D printer. First, the experimental analysis was performed to find the optimal sintering temperature of Zeolite in terms of removal rate and material strength, and a compressive strength test for a 3D printed ceramic composite was carried out to confirm structural integrity. Then, we conducted a CFD analysis to investigate the effect of flow velocity and pressure drop distribution through the conventional packed bead ion exchange (PB-IEX) resins and the proposed Twisted Honeycomb ion exchanger (TH-IEX). We focused on the pressure force distribution, which is important for ion exchange immobilization and degradation. The flow velocity and retention time through the ion exchanger play an essential role regarding the adsorption rate. A wide range of beads diameter [0.001-1.0 mm] has been analyzed. Larger beads decrease the pressure drop with a reduction of removal rate. The proposed twisted honeycomb shape shows better flow velocity distribution and less pressure drop. Finally, structural analysis was performed using ANSYS FEM to investigate the influence of flow distribution on the integrity of the Twisted Honeycomb ion exchanger, in which the FEM model was validated against the compressive strength experimental data. As a result, we are proposing the prototype of high efficiency ion exchanger.