Abstract
From the viewpoint of energy security in Japan and the reduction of the environmental load, the continuous operation of light water reactors is essential. Since a pH adjuster with enriched Li-7 ions is required for water quality control on PWR, the development of Li-7 enrichment technology is one of the key issues. The multi-channel counter-current electrophoresis (MCCCE) method has been developed as a technology with a low environmental load. To put this method into practical use, it is necessary to understand the behavior of Li-7 ions in the channel flow and optimize the experimental condition to separate Li-7 and its isotope. In this paper, to understand the behavior of Li-7 ions in a single channel of the experimental apparatus, a numerical simulation method based on a computational fluid dynamics (CFD) code with a particle tracking method, TPFIT-LPT, was developed. In the method, the motion of each representative ion in the flow is evaluated using the particle as a mass point moving along the flow under an electric field. The difference in the isotopes was represented by changes in the magnitude of the added velocity. We also considered that although it is impossible to measure the behavior of each ion, it is important to measure the flow velocity of the bulk fluid for the validation of the numerical simulation. We developed a lab-scale experimental apparatus in which the single channel of the actual apparatus was simplified to measure the flow velocity by Particle Image Velocimetry (PIV). We set a pulsation flow condition on the lab-scale experiment, which is one of the difficult conditions for the numerical simulation and measured the velocity. As the result, we confirmed that the pulsation flow was reproduced. We set the measured data as the inlet boundary condition of the numerical simulation and conducted it. As the numerical result, we confirmed that the ions affected by the electric field moved upstream with pulsation. We also confirmed the effect of the electric field on the motion of the ions.
